var ZLMRTCClient = (function (exports) {
  'use strict'

  const Events$1 = {
    WEBRTC_NOT_SUPPORT: 'WEBRTC_NOT_SUPPORT',
    WEBRTC_ICE_CANDIDATE_ERROR: 'WEBRTC_ICE_CANDIDATE_ERROR',
    WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED: 'WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED',
    WEBRTC_ON_REMOTE_STREAMS: 'WEBRTC_ON_REMOTE_STREAMS',
    WEBRTC_ON_LOCAL_STREAM: 'WEBRTC_ON_LOCAL_STREAM',
    WEBRTC_ON_CONNECTION_STATE_CHANGE: 'WEBRTC_ON_CONNECTION_STATE_CHANGE',
    CAPTURE_STREAM_FAILED: 'CAPTURE_STREAM_FAILED',
  }

  const VERSION = '1.0.1'
  const BUILD_DATE = 'Sat Jan 08 2022 15:24:38 GMT+0800 (China Standard Time)'

  // Copyright (C) <2018> Intel Corporation
  //
  // SPDX-License-Identifier: Apache-2.0
  // eslint-disable-next-line require-jsdoc
  function isFirefox() {
    return window.navigator.userAgent.match('Firefox') !== null
  } // eslint-disable-next-line require-jsdoc

  function isChrome() {
    return window.navigator.userAgent.match('Chrome') !== null
  } // eslint-disable-next-line require-jsdoc

  function isEdge() {
    return window.navigator.userAgent.match(/Edge\/(\d+).(\d+)$/) !== null
  } // eslint-disable-next-line require-jsdoc

  // Copyright (C) <2018> Intel Corporation
  /**
   * @class AudioSourceInfo
   * @classDesc Source info about an audio track. Values: 'mic', 'screen-cast', 'file', 'mixed'.
   * @memberOf Owt.Base
   * @readonly
   * @enum {string}
   */

  const AudioSourceInfo = {
    MIC: 'mic',
    SCREENCAST: 'screen-cast',
    FILE: 'file',
    MIXED: 'mixed',
  }
  /**
   * @class VideoSourceInfo
   * @classDesc Source info about a video track. Values: 'camera', 'screen-cast', 'file', 'mixed'.
   * @memberOf Owt.Base
   * @readonly
   * @enum {string}
   */

  const VideoSourceInfo = {
    CAMERA: 'camera',
    SCREENCAST: 'screen-cast',
    FILE: 'file',
    MIXED: 'mixed',
  }
  /**
   * @class TrackKind
   * @classDesc Kind of a track. Values: 'audio' for audio track, 'video' for video track, 'av' for both audio and video tracks.
   * @memberOf Owt.Base
   * @readonly
   * @enum {string}
   */

  const TrackKind = {
    /**
     * Audio tracks.
     * @type string
     */
    AUDIO: 'audio',

    /**
     * Video tracks.
     * @type string
     */
    VIDEO: 'video',

    /**
     * Both audio and video tracks.
     * @type string
     */
    AUDIO_AND_VIDEO: 'av',
  }
  /**
   * @class Resolution
   * @memberOf Owt.Base
   * @classDesc The Resolution defines the size of a rectangle.
   * @constructor
   * @param {number} width
   * @param {number} height
   */

  class Resolution {
    // eslint-disable-next-line require-jsdoc
    constructor(width, height) {
      /**
       * @member {number} width
       * @instance
       * @memberof Owt.Base.Resolution
       */
      this.width = width
      /**
       * @member {number} height
       * @instance
       * @memberof Owt.Base.Resolution
       */

      this.height = height
    }
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  let logDisabled_ = true
  let deprecationWarnings_ = true

  /**
   * Extract browser version out of the provided user agent string.
   *
   * @param {!string} uastring userAgent string.
   * @param {!string} expr Regular expression used as match criteria.
   * @param {!number} pos position in the version string to be returned.
   * @return {!number} browser version.
   */
  function extractVersion(uastring, expr, pos) {
    const match = uastring.match(expr)
    return match && match.length >= pos && parseInt(match[pos], 10)
  }

  // Wraps the peerconnection event eventNameToWrap in a function
  // which returns the modified event object (or false to prevent
  // the event).
  function wrapPeerConnectionEvent(window, eventNameToWrap, wrapper) {
    if (!window.RTCPeerConnection) {
      return
    }
    const proto = window.RTCPeerConnection.prototype
    const nativeAddEventListener = proto.addEventListener
    proto.addEventListener = function (nativeEventName, cb) {
      if (nativeEventName !== eventNameToWrap) {
        return nativeAddEventListener.apply(this, arguments)
      }
      const wrappedCallback = (e) => {
        const modifiedEvent = wrapper(e)
        if (modifiedEvent) {
          if (cb.handleEvent) {
            cb.handleEvent(modifiedEvent)
          } else {
            cb(modifiedEvent)
          }
        }
      }
      this._eventMap = this._eventMap || {}
      if (!this._eventMap[eventNameToWrap]) {
        this._eventMap[eventNameToWrap] = new Map()
      }
      this._eventMap[eventNameToWrap].set(cb, wrappedCallback)
      return nativeAddEventListener.apply(this, [nativeEventName, wrappedCallback])
    }

    const nativeRemoveEventListener = proto.removeEventListener
    proto.removeEventListener = function (nativeEventName, cb) {
      if (
        nativeEventName !== eventNameToWrap ||
        !this._eventMap ||
        !this._eventMap[eventNameToWrap]
      ) {
        return nativeRemoveEventListener.apply(this, arguments)
      }
      if (!this._eventMap[eventNameToWrap].has(cb)) {
        return nativeRemoveEventListener.apply(this, arguments)
      }
      const unwrappedCb = this._eventMap[eventNameToWrap].get(cb)
      this._eventMap[eventNameToWrap].delete(cb)
      if (this._eventMap[eventNameToWrap].size === 0) {
        delete this._eventMap[eventNameToWrap]
      }
      if (Object.keys(this._eventMap).length === 0) {
        delete this._eventMap
      }
      return nativeRemoveEventListener.apply(this, [nativeEventName, unwrappedCb])
    }

    Object.defineProperty(proto, 'on' + eventNameToWrap, {
      get() {
        return this['_on' + eventNameToWrap]
      },
      set(cb) {
        if (this['_on' + eventNameToWrap]) {
          this.removeEventListener(eventNameToWrap, this['_on' + eventNameToWrap])
          delete this['_on' + eventNameToWrap]
        }
        if (cb) {
          this.addEventListener(eventNameToWrap, (this['_on' + eventNameToWrap] = cb))
        }
      },
      enumerable: true,
      configurable: true,
    })
  }

  function disableLog(bool) {
    if (typeof bool !== 'boolean') {
      return new Error('Argument type: ' + typeof bool + '. Please use a boolean.')
    }
    logDisabled_ = bool
    return bool ? 'adapter.js logging disabled' : 'adapter.js logging enabled'
  }

  /**
   * Disable or enable deprecation warnings
   * @param {!boolean} bool set to true to disable warnings.
   */
  function disableWarnings(bool) {
    if (typeof bool !== 'boolean') {
      return new Error('Argument type: ' + typeof bool + '. Please use a boolean.')
    }
    deprecationWarnings_ = !bool
    return 'adapter.js deprecation warnings ' + (bool ? 'disabled' : 'enabled')
  }

  function log$1() {
    if (typeof window === 'object') {
      if (logDisabled_) {
        return
      }
      if (typeof console !== 'undefined' && typeof console.log === 'function') {
        console.log.apply(console, arguments)
      }
    }
  }

  /**
   * Shows a deprecation warning suggesting the modern and spec-compatible API.
   */
  function deprecated(oldMethod, newMethod) {
    if (!deprecationWarnings_) {
      return
    }
    console.warn(oldMethod + ' is deprecated, please use ' + newMethod + ' instead.')
  }

  /**
   * Browser detector.
   *
   * @return {object} result containing browser and version
   *     properties.
   */
  function detectBrowser(window) {
    // Returned result object.
    const result = { browser: null, version: null }

    // Fail early if it's not a browser
    if (typeof window === 'undefined' || !window.navigator) {
      result.browser = 'Not a browser.'
      return result
    }

    const { navigator } = window

    if (navigator.mozGetUserMedia) {
      // Firefox.
      result.browser = 'firefox'
      result.version = extractVersion(navigator.userAgent, /Firefox\/(\d+)\./, 1)
    } else if (
      navigator.webkitGetUserMedia ||
      (window.isSecureContext === false && window.webkitRTCPeerConnection && !window.RTCIceGatherer)
    ) {
      // Chrome, Chromium, Webview, Opera.
      // Version matches Chrome/WebRTC version.
      // Chrome 74 removed webkitGetUserMedia on http as well so we need the
      // more complicated fallback to webkitRTCPeerConnection.
      result.browser = 'chrome'
      result.version = extractVersion(navigator.userAgent, /Chrom(e|ium)\/(\d+)\./, 2)
    } else if (navigator.mediaDevices && navigator.userAgent.match(/Edge\/(\d+).(\d+)$/)) {
      // Edge.
      result.browser = 'edge'
      result.version = extractVersion(navigator.userAgent, /Edge\/(\d+).(\d+)$/, 2)
    } else if (window.RTCPeerConnection && navigator.userAgent.match(/AppleWebKit\/(\d+)\./)) {
      // Safari.
      result.browser = 'safari'
      result.version = extractVersion(navigator.userAgent, /AppleWebKit\/(\d+)\./, 1)
      result.supportsUnifiedPlan =
        window.RTCRtpTransceiver && 'currentDirection' in window.RTCRtpTransceiver.prototype
    } else {
      // Default fallthrough: not supported.
      result.browser = 'Not a supported browser.'
      return result
    }

    return result
  }

  /**
   * Checks if something is an object.
   *
   * @param {*} val The something you want to check.
   * @return true if val is an object, false otherwise.
   */
  function isObject$1(val) {
    return Object.prototype.toString.call(val) === '[object Object]'
  }

  /**
   * Remove all empty objects and undefined values
   * from a nested object -- an enhanced and vanilla version
   * of Lodash's `compact`.
   */
  function compactObject(data) {
    if (!isObject$1(data)) {
      return data
    }

    return Object.keys(data).reduce(function (accumulator, key) {
      const isObj = isObject$1(data[key])
      const value = isObj ? compactObject(data[key]) : data[key]
      const isEmptyObject = isObj && !Object.keys(value).length
      if (value === undefined || isEmptyObject) {
        return accumulator
      }
      return Object.assign(accumulator, { [key]: value })
    }, {})
  }

  /* iterates the stats graph recursively. */
  function walkStats(stats, base, resultSet) {
    if (!base || resultSet.has(base.id)) {
      return
    }
    resultSet.set(base.id, base)
    Object.keys(base).forEach((name) => {
      if (name.endsWith('Id')) {
        walkStats(stats, stats.get(base[name]), resultSet)
      } else if (name.endsWith('Ids')) {
        base[name].forEach((id) => {
          walkStats(stats, stats.get(id), resultSet)
        })
      }
    })
  }

  /* filter getStats for a sender/receiver track. */
  function filterStats(result, track, outbound) {
    const streamStatsType = outbound ? 'outbound-rtp' : 'inbound-rtp'
    const filteredResult = new Map()
    if (track === null) {
      return filteredResult
    }
    const trackStats = []
    result.forEach((value) => {
      if (value.type === 'track' && value.trackIdentifier === track.id) {
        trackStats.push(value)
      }
    })
    trackStats.forEach((trackStat) => {
      result.forEach((stats) => {
        if (stats.type === streamStatsType && stats.trackId === trackStat.id) {
          walkStats(result, stats, filteredResult)
        }
      })
    })
    return filteredResult
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */
  const logging = log$1

  function shimGetUserMedia$3(window, browserDetails) {
    const navigator = window && window.navigator

    if (!navigator.mediaDevices) {
      return
    }

    const constraintsToChrome_ = function (c) {
      if (typeof c !== 'object' || c.mandatory || c.optional) {
        return c
      }
      const cc = {}
      Object.keys(c).forEach((key) => {
        if (key === 'require' || key === 'advanced' || key === 'mediaSource') {
          return
        }
        const r = typeof c[key] === 'object' ? c[key] : { ideal: c[key] }
        if (r.exact !== undefined && typeof r.exact === 'number') {
          r.min = r.max = r.exact
        }
        const oldname_ = function (prefix, name) {
          if (prefix) {
            return prefix + name.charAt(0).toUpperCase() + name.slice(1)
          }
          return name === 'deviceId' ? 'sourceId' : name
        }
        if (r.ideal !== undefined) {
          cc.optional = cc.optional || []
          let oc = {}
          if (typeof r.ideal === 'number') {
            oc[oldname_('min', key)] = r.ideal
            cc.optional.push(oc)
            oc = {}
            oc[oldname_('max', key)] = r.ideal
            cc.optional.push(oc)
          } else {
            oc[oldname_('', key)] = r.ideal
            cc.optional.push(oc)
          }
        }
        if (r.exact !== undefined && typeof r.exact !== 'number') {
          cc.mandatory = cc.mandatory || {}
          cc.mandatory[oldname_('', key)] = r.exact
        } else {
          ;['min', 'max'].forEach((mix) => {
            if (r[mix] !== undefined) {
              cc.mandatory = cc.mandatory || {}
              cc.mandatory[oldname_(mix, key)] = r[mix]
            }
          })
        }
      })
      if (c.advanced) {
        cc.optional = (cc.optional || []).concat(c.advanced)
      }
      return cc
    }

    const shimConstraints_ = function (constraints, func) {
      if (browserDetails.version >= 61) {
        return func(constraints)
      }
      constraints = JSON.parse(JSON.stringify(constraints))
      if (constraints && typeof constraints.audio === 'object') {
        const remap = function (obj, a, b) {
          if (a in obj && !(b in obj)) {
            obj[b] = obj[a]
            delete obj[a]
          }
        }
        constraints = JSON.parse(JSON.stringify(constraints))
        remap(constraints.audio, 'autoGainControl', 'googAutoGainControl')
        remap(constraints.audio, 'noiseSuppression', 'googNoiseSuppression')
        constraints.audio = constraintsToChrome_(constraints.audio)
      }
      if (constraints && typeof constraints.video === 'object') {
        // Shim facingMode for mobile & surface pro.
        let face = constraints.video.facingMode
        face = face && (typeof face === 'object' ? face : { ideal: face })
        const getSupportedFacingModeLies = browserDetails.version < 66

        if (
          face &&
          (face.exact === 'user' ||
            face.exact === 'environment' ||
            face.ideal === 'user' ||
            face.ideal === 'environment') &&
          !(
            navigator.mediaDevices.getSupportedConstraints &&
            navigator.mediaDevices.getSupportedConstraints().facingMode &&
            !getSupportedFacingModeLies
          )
        ) {
          delete constraints.video.facingMode
          let matches
          if (face.exact === 'environment' || face.ideal === 'environment') {
            matches = ['back', 'rear']
          } else if (face.exact === 'user' || face.ideal === 'user') {
            matches = ['front']
          }
          if (matches) {
            // Look for matches in label, or use last cam for back (typical).
            return navigator.mediaDevices.enumerateDevices().then((devices) => {
              devices = devices.filter((d) => d.kind === 'videoinput')
              let dev = devices.find((d) =>
                matches.some((match) => d.label.toLowerCase().includes(match))
              )
              if (!dev && devices.length && matches.includes('back')) {
                dev = devices[devices.length - 1] // more likely the back cam
              }
              if (dev) {
                constraints.video.deviceId = face.exact
                  ? { exact: dev.deviceId }
                  : { ideal: dev.deviceId }
              }
              constraints.video = constraintsToChrome_(constraints.video)
              logging('chrome: ' + JSON.stringify(constraints))
              return func(constraints)
            })
          }
        }
        constraints.video = constraintsToChrome_(constraints.video)
      }
      logging('chrome: ' + JSON.stringify(constraints))
      return func(constraints)
    }

    const shimError_ = function (e) {
      if (browserDetails.version >= 64) {
        return e
      }
      return {
        name:
          {
            PermissionDeniedError: 'NotAllowedError',
            PermissionDismissedError: 'NotAllowedError',
            InvalidStateError: 'NotAllowedError',
            DevicesNotFoundError: 'NotFoundError',
            ConstraintNotSatisfiedError: 'OverconstrainedError',
            TrackStartError: 'NotReadableError',
            MediaDeviceFailedDueToShutdown: 'NotAllowedError',
            MediaDeviceKillSwitchOn: 'NotAllowedError',
            TabCaptureError: 'AbortError',
            ScreenCaptureError: 'AbortError',
            DeviceCaptureError: 'AbortError',
          }[e.name] || e.name,
        message: e.message,
        constraint: e.constraint || e.constraintName,
        toString() {
          return this.name + (this.message && ': ') + this.message
        },
      }
    }

    const getUserMedia_ = function (constraints, onSuccess, onError) {
      shimConstraints_(constraints, (c) => {
        navigator.webkitGetUserMedia(c, onSuccess, (e) => {
          if (onError) {
            onError(shimError_(e))
          }
        })
      })
    }
    navigator.getUserMedia = getUserMedia_.bind(navigator)

    // Even though Chrome 45 has navigator.mediaDevices and a getUserMedia
    // function which returns a Promise, it does not accept spec-style
    // constraints.
    if (navigator.mediaDevices.getUserMedia) {
      const origGetUserMedia = navigator.mediaDevices.getUserMedia.bind(navigator.mediaDevices)
      navigator.mediaDevices.getUserMedia = function (cs) {
        return shimConstraints_(cs, (c) =>
          origGetUserMedia(c).then(
            (stream) => {
              if (
                (c.audio && !stream.getAudioTracks().length) ||
                (c.video && !stream.getVideoTracks().length)
              ) {
                stream.getTracks().forEach((track) => {
                  track.stop()
                })
                throw new DOMException('', 'NotFoundError')
              }
              return stream
            },
            (e) => Promise.reject(shimError_(e))
          )
        )
      }
    }
  }

  /*
   *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */
  function shimGetDisplayMedia$2(window, getSourceId) {
    if (window.navigator.mediaDevices && 'getDisplayMedia' in window.navigator.mediaDevices) {
      return
    }
    if (!window.navigator.mediaDevices) {
      return
    }
    // getSourceId is a function that returns a promise resolving with
    // the sourceId of the screen/window/tab to be shared.
    if (typeof getSourceId !== 'function') {
      console.error('shimGetDisplayMedia: getSourceId argument is not ' + 'a function')
      return
    }
    window.navigator.mediaDevices.getDisplayMedia = function getDisplayMedia(constraints) {
      return getSourceId(constraints).then((sourceId) => {
        const widthSpecified = constraints.video && constraints.video.width
        const heightSpecified = constraints.video && constraints.video.height
        const frameRateSpecified = constraints.video && constraints.video.frameRate
        constraints.video = {
          mandatory: {
            chromeMediaSource: 'desktop',
            chromeMediaSourceId: sourceId,
            maxFrameRate: frameRateSpecified || 3,
          },
        }
        if (widthSpecified) {
          constraints.video.mandatory.maxWidth = widthSpecified
        }
        if (heightSpecified) {
          constraints.video.mandatory.maxHeight = heightSpecified
        }
        return window.navigator.mediaDevices.getUserMedia(constraints)
      })
    }
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimMediaStream(window) {
    window.MediaStream = window.MediaStream || window.webkitMediaStream
  }

  function shimOnTrack$1(window) {
    if (
      typeof window === 'object' &&
      window.RTCPeerConnection &&
      !('ontrack' in window.RTCPeerConnection.prototype)
    ) {
      Object.defineProperty(window.RTCPeerConnection.prototype, 'ontrack', {
        get() {
          return this._ontrack
        },
        set(f) {
          if (this._ontrack) {
            this.removeEventListener('track', this._ontrack)
          }
          this.addEventListener('track', (this._ontrack = f))
        },
        enumerable: true,
        configurable: true,
      })
      const origSetRemoteDescription = window.RTCPeerConnection.prototype.setRemoteDescription
      window.RTCPeerConnection.prototype.setRemoteDescription = function setRemoteDescription() {
        if (!this._ontrackpoly) {
          this._ontrackpoly = (e) => {
            // onaddstream does not fire when a track is added to an existing
            // stream. But stream.onaddtrack is implemented so we use that.
            e.stream.addEventListener('addtrack', (te) => {
              let receiver
              if (window.RTCPeerConnection.prototype.getReceivers) {
                receiver = this.getReceivers().find((r) => r.track && r.track.id === te.track.id)
              } else {
                receiver = { track: te.track }
              }

              const event = new Event('track')
              event.track = te.track
              event.receiver = receiver
              event.transceiver = { receiver }
              event.streams = [e.stream]
              this.dispatchEvent(event)
            })
            e.stream.getTracks().forEach((track) => {
              let receiver
              if (window.RTCPeerConnection.prototype.getReceivers) {
                receiver = this.getReceivers().find((r) => r.track && r.track.id === track.id)
              } else {
                receiver = { track }
              }
              const event = new Event('track')
              event.track = track
              event.receiver = receiver
              event.transceiver = { receiver }
              event.streams = [e.stream]
              this.dispatchEvent(event)
            })
          }
          this.addEventListener('addstream', this._ontrackpoly)
        }
        return origSetRemoteDescription.apply(this, arguments)
      }
    } else {
      // even if RTCRtpTransceiver is in window, it is only used and
      // emitted in unified-plan. Unfortunately this means we need
      // to unconditionally wrap the event.
      wrapPeerConnectionEvent(window, 'track', (e) => {
        if (!e.transceiver) {
          Object.defineProperty(e, 'transceiver', { value: { receiver: e.receiver } })
        }
        return e
      })
    }
  }

  function shimGetSendersWithDtmf(window) {
    // Overrides addTrack/removeTrack, depends on shimAddTrackRemoveTrack.
    if (
      typeof window === 'object' &&
      window.RTCPeerConnection &&
      !('getSenders' in window.RTCPeerConnection.prototype) &&
      'createDTMFSender' in window.RTCPeerConnection.prototype
    ) {
      const shimSenderWithDtmf = function (pc, track) {
        return {
          track,
          get dtmf() {
            if (this._dtmf === undefined) {
              if (track.kind === 'audio') {
                this._dtmf = pc.createDTMFSender(track)
              } else {
                this._dtmf = null
              }
            }
            return this._dtmf
          },
          _pc: pc,
        }
      }

      // augment addTrack when getSenders is not available.
      if (!window.RTCPeerConnection.prototype.getSenders) {
        window.RTCPeerConnection.prototype.getSenders = function getSenders() {
          this._senders = this._senders || []
          return this._senders.slice() // return a copy of the internal state.
        }
        const origAddTrack = window.RTCPeerConnection.prototype.addTrack
        window.RTCPeerConnection.prototype.addTrack = function addTrack(track, stream) {
          let sender = origAddTrack.apply(this, arguments)
          if (!sender) {
            sender = shimSenderWithDtmf(this, track)
            this._senders.push(sender)
          }
          return sender
        }

        const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack
        window.RTCPeerConnection.prototype.removeTrack = function removeTrack(sender) {
          origRemoveTrack.apply(this, arguments)
          const idx = this._senders.indexOf(sender)
          if (idx !== -1) {
            this._senders.splice(idx, 1)
          }
        }
      }
      const origAddStream = window.RTCPeerConnection.prototype.addStream
      window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
        this._senders = this._senders || []
        origAddStream.apply(this, [stream])
        stream.getTracks().forEach((track) => {
          this._senders.push(shimSenderWithDtmf(this, track))
        })
      }

      const origRemoveStream = window.RTCPeerConnection.prototype.removeStream
      window.RTCPeerConnection.prototype.removeStream = function removeStream(stream) {
        this._senders = this._senders || []
        origRemoveStream.apply(this, [stream])

        stream.getTracks().forEach((track) => {
          const sender = this._senders.find((s) => s.track === track)
          if (sender) {
            // remove sender
            this._senders.splice(this._senders.indexOf(sender), 1)
          }
        })
      }
    } else if (
      typeof window === 'object' &&
      window.RTCPeerConnection &&
      'getSenders' in window.RTCPeerConnection.prototype &&
      'createDTMFSender' in window.RTCPeerConnection.prototype &&
      window.RTCRtpSender &&
      !('dtmf' in window.RTCRtpSender.prototype)
    ) {
      const origGetSenders = window.RTCPeerConnection.prototype.getSenders
      window.RTCPeerConnection.prototype.getSenders = function getSenders() {
        const senders = origGetSenders.apply(this, [])
        senders.forEach((sender) => (sender._pc = this))
        return senders
      }

      Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
        get() {
          if (this._dtmf === undefined) {
            if (this.track.kind === 'audio') {
              this._dtmf = this._pc.createDTMFSender(this.track)
            } else {
              this._dtmf = null
            }
          }
          return this._dtmf
        },
      })
    }
  }

  function shimGetStats(window) {
    if (!window.RTCPeerConnection) {
      return
    }

    const origGetStats = window.RTCPeerConnection.prototype.getStats
    window.RTCPeerConnection.prototype.getStats = function getStats() {
      const [selector, onSucc, onErr] = arguments

      // If selector is a function then we are in the old style stats so just
      // pass back the original getStats format to avoid breaking old users.
      if (arguments.length > 0 && typeof selector === 'function') {
        return origGetStats.apply(this, arguments)
      }

      // When spec-style getStats is supported, return those when called with
      // either no arguments or the selector argument is null.
      if (origGetStats.length === 0 && (arguments.length === 0 || typeof selector !== 'function')) {
        return origGetStats.apply(this, [])
      }

      const fixChromeStats_ = function (response) {
        const standardReport = {}
        const reports = response.result()
        reports.forEach((report) => {
          const standardStats = {
            id: report.id,
            timestamp: report.timestamp,
            type:
              {
                localcandidate: 'local-candidate',
                remotecandidate: 'remote-candidate',
              }[report.type] || report.type,
          }
          report.names().forEach((name) => {
            standardStats[name] = report.stat(name)
          })
          standardReport[standardStats.id] = standardStats
        })

        return standardReport
      }

      // shim getStats with maplike support
      const makeMapStats = function (stats) {
        return new Map(Object.keys(stats).map((key) => [key, stats[key]]))
      }

      if (arguments.length >= 2) {
        const successCallbackWrapper_ = function (response) {
          onSucc(makeMapStats(fixChromeStats_(response)))
        }

        return origGetStats.apply(this, [successCallbackWrapper_, selector])
      }

      // promise-support
      return new Promise((resolve, reject) => {
        origGetStats.apply(this, [
          function (response) {
            resolve(makeMapStats(fixChromeStats_(response)))
          },
          reject,
        ])
      }).then(onSucc, onErr)
    }
  }

  function shimSenderReceiverGetStats(window) {
    if (
      !(
        typeof window === 'object' &&
        window.RTCPeerConnection &&
        window.RTCRtpSender &&
        window.RTCRtpReceiver
      )
    ) {
      return
    }

    // shim sender stats.
    if (!('getStats' in window.RTCRtpSender.prototype)) {
      const origGetSenders = window.RTCPeerConnection.prototype.getSenders
      if (origGetSenders) {
        window.RTCPeerConnection.prototype.getSenders = function getSenders() {
          const senders = origGetSenders.apply(this, [])
          senders.forEach((sender) => (sender._pc = this))
          return senders
        }
      }

      const origAddTrack = window.RTCPeerConnection.prototype.addTrack
      if (origAddTrack) {
        window.RTCPeerConnection.prototype.addTrack = function addTrack() {
          const sender = origAddTrack.apply(this, arguments)
          sender._pc = this
          return sender
        }
      }
      window.RTCRtpSender.prototype.getStats = function getStats() {
        const sender = this
        return this._pc.getStats().then((result) =>
          /* Note: this will include stats of all senders that
           *   send a track with the same id as sender.track as
           *   it is not possible to identify the RTCRtpSender.
           */
          filterStats(result, sender.track, true)
        )
      }
    }

    // shim receiver stats.
    if (!('getStats' in window.RTCRtpReceiver.prototype)) {
      const origGetReceivers = window.RTCPeerConnection.prototype.getReceivers
      if (origGetReceivers) {
        window.RTCPeerConnection.prototype.getReceivers = function getReceivers() {
          const receivers = origGetReceivers.apply(this, [])
          receivers.forEach((receiver) => (receiver._pc = this))
          return receivers
        }
      }
      wrapPeerConnectionEvent(window, 'track', (e) => {
        e.receiver._pc = e.srcElement
        return e
      })
      window.RTCRtpReceiver.prototype.getStats = function getStats() {
        const receiver = this
        return this._pc.getStats().then((result) => filterStats(result, receiver.track, false))
      }
    }

    if (
      !(
        'getStats' in window.RTCRtpSender.prototype && 'getStats' in window.RTCRtpReceiver.prototype
      )
    ) {
      return
    }

    // shim RTCPeerConnection.getStats(track).
    const origGetStats = window.RTCPeerConnection.prototype.getStats
    window.RTCPeerConnection.prototype.getStats = function getStats() {
      if (arguments.length > 0 && arguments[0] instanceof window.MediaStreamTrack) {
        const track = arguments[0]
        let sender
        let receiver
        let err
        this.getSenders().forEach((s) => {
          if (s.track === track) {
            if (sender) {
              err = true
            } else {
              sender = s
            }
          }
        })
        this.getReceivers().forEach((r) => {
          if (r.track === track) {
            if (receiver) {
              err = true
            } else {
              receiver = r
            }
          }
          return r.track === track
        })
        if (err || (sender && receiver)) {
          return Promise.reject(
            new DOMException(
              'There are more than one sender or receiver for the track.',
              'InvalidAccessError'
            )
          )
        } else if (sender) {
          return sender.getStats()
        } else if (receiver) {
          return receiver.getStats()
        }
        return Promise.reject(
          new DOMException('There is no sender or receiver for the track.', 'InvalidAccessError')
        )
      }
      return origGetStats.apply(this, arguments)
    }
  }

  function shimAddTrackRemoveTrackWithNative(window) {
    // shim addTrack/removeTrack with native variants in order to make
    // the interactions with legacy getLocalStreams behave as in other browsers.
    // Keeps a mapping stream.id => [stream, rtpsenders...]
    window.RTCPeerConnection.prototype.getLocalStreams = function getLocalStreams() {
      this._shimmedLocalStreams = this._shimmedLocalStreams || {}
      return Object.keys(this._shimmedLocalStreams).map(
        (streamId) => this._shimmedLocalStreams[streamId][0]
      )
    }

    const origAddTrack = window.RTCPeerConnection.prototype.addTrack
    window.RTCPeerConnection.prototype.addTrack = function addTrack(track, stream) {
      if (!stream) {
        return origAddTrack.apply(this, arguments)
      }
      this._shimmedLocalStreams = this._shimmedLocalStreams || {}

      const sender = origAddTrack.apply(this, arguments)
      if (!this._shimmedLocalStreams[stream.id]) {
        this._shimmedLocalStreams[stream.id] = [stream, sender]
      } else if (this._shimmedLocalStreams[stream.id].indexOf(sender) === -1) {
        this._shimmedLocalStreams[stream.id].push(sender)
      }
      return sender
    }

    const origAddStream = window.RTCPeerConnection.prototype.addStream
    window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
      this._shimmedLocalStreams = this._shimmedLocalStreams || {}

      stream.getTracks().forEach((track) => {
        const alreadyExists = this.getSenders().find((s) => s.track === track)
        if (alreadyExists) {
          throw new DOMException('Track already exists.', 'InvalidAccessError')
        }
      })
      const existingSenders = this.getSenders()
      origAddStream.apply(this, arguments)
      const newSenders = this.getSenders().filter(
        (newSender) => existingSenders.indexOf(newSender) === -1
      )
      this._shimmedLocalStreams[stream.id] = [stream].concat(newSenders)
    }

    const origRemoveStream = window.RTCPeerConnection.prototype.removeStream
    window.RTCPeerConnection.prototype.removeStream = function removeStream(stream) {
      this._shimmedLocalStreams = this._shimmedLocalStreams || {}
      delete this._shimmedLocalStreams[stream.id]
      return origRemoveStream.apply(this, arguments)
    }

    const origRemoveTrack = window.RTCPeerConnection.prototype.removeTrack
    window.RTCPeerConnection.prototype.removeTrack = function removeTrack(sender) {
      this._shimmedLocalStreams = this._shimmedLocalStreams || {}
      if (sender) {
        Object.keys(this._shimmedLocalStreams).forEach((streamId) => {
          const idx = this._shimmedLocalStreams[streamId].indexOf(sender)
          if (idx !== -1) {
            this._shimmedLocalStreams[streamId].splice(idx, 1)
          }
          if (this._shimmedLocalStreams[streamId].length === 1) {
            delete this._shimmedLocalStreams[streamId]
          }
        })
      }
      return origRemoveTrack.apply(this, arguments)
    }
  }

  function shimAddTrackRemoveTrack(window, browserDetails) {
    if (!window.RTCPeerConnection) {
      return
    }
    // shim addTrack and removeTrack.
    if (window.RTCPeerConnection.prototype.addTrack && browserDetails.version >= 65) {
      return shimAddTrackRemoveTrackWithNative(window)
    }

    // also shim pc.getLocalStreams when addTrack is shimmed
    // to return the original streams.
    const origGetLocalStreams = window.RTCPeerConnection.prototype.getLocalStreams
    window.RTCPeerConnection.prototype.getLocalStreams = function getLocalStreams() {
      const nativeStreams = origGetLocalStreams.apply(this)
      this._reverseStreams = this._reverseStreams || {}
      return nativeStreams.map((stream) => this._reverseStreams[stream.id])
    }

    const origAddStream = window.RTCPeerConnection.prototype.addStream
    window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
      this._streams = this._streams || {}
      this._reverseStreams = this._reverseStreams || {}

      stream.getTracks().forEach((track) => {
        const alreadyExists = this.getSenders().find((s) => s.track === track)
        if (alreadyExists) {
          throw new DOMException('Track already exists.', 'InvalidAccessError')
        }
      })
      // Add identity mapping for consistency with addTrack.
      // Unless this is being used with a stream from addTrack.
      if (!this._reverseStreams[stream.id]) {
        const newStream = new window.MediaStream(stream.getTracks())
        this._streams[stream.id] = newStream
        this._reverseStreams[newStream.id] = stream
        stream = newStream
      }
      origAddStream.apply(this, [stream])
    }

    const origRemoveStream = window.RTCPeerConnection.prototype.removeStream
    window.RTCPeerConnection.prototype.removeStream = function removeStream(stream) {
      this._streams = this._streams || {}
      this._reverseStreams = this._reverseStreams || {}

      origRemoveStream.apply(this, [this._streams[stream.id] || stream])
      delete this._reverseStreams[
        this._streams[stream.id] ? this._streams[stream.id].id : stream.id
      ]
      delete this._streams[stream.id]
    }

    window.RTCPeerConnection.prototype.addTrack = function addTrack(track, stream) {
      if (this.signalingState === 'closed') {
        throw new DOMException(
          "The RTCPeerConnection's signalingState is 'closed'.",
          'InvalidStateError'
        )
      }
      const streams = [].slice.call(arguments, 1)
      if (streams.length !== 1 || !streams[0].getTracks().find((t) => t === track)) {
        // this is not fully correct but all we can manage without
        // [[associated MediaStreams]] internal slot.
        throw new DOMException(
          'The adapter.js addTrack polyfill only supports a single ' +
            ' stream which is associated with the specified track.',
          'NotSupportedError'
        )
      }

      const alreadyExists = this.getSenders().find((s) => s.track === track)
      if (alreadyExists) {
        throw new DOMException('Track already exists.', 'InvalidAccessError')
      }

      this._streams = this._streams || {}
      this._reverseStreams = this._reverseStreams || {}
      const oldStream = this._streams[stream.id]
      if (oldStream) {
        // this is using odd Chrome behaviour, use with caution:
        // https://bugs.chromium.org/p/webrtc/issues/detail?id=7815
        // Note: we rely on the high-level addTrack/dtmf shim to
        // create the sender with a dtmf sender.
        oldStream.addTrack(track)

        // Trigger ONN async.
        Promise.resolve().then(() => {
          this.dispatchEvent(new Event('negotiationneeded'))
        })
      } else {
        const newStream = new window.MediaStream([track])
        this._streams[stream.id] = newStream
        this._reverseStreams[newStream.id] = stream
        this.addStream(newStream)
      }
      return this.getSenders().find((s) => s.track === track)
    }

    // replace the internal stream id with the external one and
    // vice versa.
    function replaceInternalStreamId(pc, description) {
      let sdp = description.sdp
      Object.keys(pc._reverseStreams || []).forEach((internalId) => {
        const externalStream = pc._reverseStreams[internalId]
        const internalStream = pc._streams[externalStream.id]
        sdp = sdp.replace(new RegExp(internalStream.id, 'g'), externalStream.id)
      })
      return new RTCSessionDescription({
        type: description.type,
        sdp,
      })
    }
    function replaceExternalStreamId(pc, description) {
      let sdp = description.sdp
      Object.keys(pc._reverseStreams || []).forEach((internalId) => {
        const externalStream = pc._reverseStreams[internalId]
        const internalStream = pc._streams[externalStream.id]
        sdp = sdp.replace(new RegExp(externalStream.id, 'g'), internalStream.id)
      })
      return new RTCSessionDescription({
        type: description.type,
        sdp,
      })
    }
    ;['createOffer', 'createAnswer'].forEach(function (method) {
      const nativeMethod = window.RTCPeerConnection.prototype[method]
      const methodObj = {
        [method]() {
          const args = arguments
          const isLegacyCall = arguments.length && typeof arguments[0] === 'function'
          if (isLegacyCall) {
            return nativeMethod.apply(this, [
              (description) => {
                const desc = replaceInternalStreamId(this, description)
                args[0].apply(null, [desc])
              },
              (err) => {
                if (args[1]) {
                  args[1].apply(null, err)
                }
              },
              arguments[2],
            ])
          }
          return nativeMethod
            .apply(this, arguments)
            .then((description) => replaceInternalStreamId(this, description))
        },
      }
      window.RTCPeerConnection.prototype[method] = methodObj[method]
    })

    const origSetLocalDescription = window.RTCPeerConnection.prototype.setLocalDescription
    window.RTCPeerConnection.prototype.setLocalDescription = function setLocalDescription() {
      if (!arguments.length || !arguments[0].type) {
        return origSetLocalDescription.apply(this, arguments)
      }
      arguments[0] = replaceExternalStreamId(this, arguments[0])
      return origSetLocalDescription.apply(this, arguments)
    }

    // TODO: mangle getStats: https://w3c.github.io/webrtc-stats/#dom-rtcmediastreamstats-streamidentifier

    const origLocalDescription = Object.getOwnPropertyDescriptor(
      window.RTCPeerConnection.prototype,
      'localDescription'
    )
    Object.defineProperty(window.RTCPeerConnection.prototype, 'localDescription', {
      get() {
        const description = origLocalDescription.get.apply(this)
        if (description.type === '') {
          return description
        }
        return replaceInternalStreamId(this, description)
      },
    })

    window.RTCPeerConnection.prototype.removeTrack = function removeTrack(sender) {
      if (this.signalingState === 'closed') {
        throw new DOMException(
          "The RTCPeerConnection's signalingState is 'closed'.",
          'InvalidStateError'
        )
      }
      // We can not yet check for sender instanceof RTCRtpSender
      // since we shim RTPSender. So we check if sender._pc is set.
      if (!sender._pc) {
        throw new DOMException(
          'Argument 1 of RTCPeerConnection.removeTrack ' +
            'does not implement interface RTCRtpSender.',
          'TypeError'
        )
      }
      const isLocal = sender._pc === this
      if (!isLocal) {
        throw new DOMException('Sender was not created by this connection.', 'InvalidAccessError')
      }

      // Search for the native stream the senders track belongs to.
      this._streams = this._streams || {}
      let stream
      Object.keys(this._streams).forEach((streamid) => {
        const hasTrack = this._streams[streamid].getTracks().find((track) => sender.track === track)
        if (hasTrack) {
          stream = this._streams[streamid]
        }
      })

      if (stream) {
        if (stream.getTracks().length === 1) {
          // if this is the last track of the stream, remove the stream. This
          // takes care of any shimmed _senders.
          this.removeStream(this._reverseStreams[stream.id])
        } else {
          // relying on the same odd chrome behaviour as above.
          stream.removeTrack(sender.track)
        }
        this.dispatchEvent(new Event('negotiationneeded'))
      }
    }
  }

  function shimPeerConnection$2(window, browserDetails) {
    if (!window.RTCPeerConnection && window.webkitRTCPeerConnection) {
      // very basic support for old versions.
      window.RTCPeerConnection = window.webkitRTCPeerConnection
    }
    if (!window.RTCPeerConnection) {
      return
    }

    // shim implicit creation of RTCSessionDescription/RTCIceCandidate
    if (browserDetails.version < 53) {
      ;['setLocalDescription', 'setRemoteDescription', 'addIceCandidate'].forEach(function (
        method
      ) {
        const nativeMethod = window.RTCPeerConnection.prototype[method]
        const methodObj = {
          [method]() {
            arguments[0] = new (
              method === 'addIceCandidate' ? window.RTCIceCandidate : window.RTCSessionDescription
            )(arguments[0])
            return nativeMethod.apply(this, arguments)
          },
        }
        window.RTCPeerConnection.prototype[method] = methodObj[method]
      })
    }
  }

  // Attempt to fix ONN in plan-b mode.
  function fixNegotiationNeeded(window, browserDetails) {
    wrapPeerConnectionEvent(window, 'negotiationneeded', (e) => {
      const pc = e.target
      if (
        browserDetails.version < 72 ||
        (pc.getConfiguration && pc.getConfiguration().sdpSemantics === 'plan-b')
      ) {
        if (pc.signalingState !== 'stable') {
          return
        }
      }
      return e
    })
  }

  var chromeShim = /*#__PURE__*/ Object.freeze({
    __proto__: null,
    shimMediaStream: shimMediaStream,
    shimOnTrack: shimOnTrack$1,
    shimGetSendersWithDtmf: shimGetSendersWithDtmf,
    shimGetStats: shimGetStats,
    shimSenderReceiverGetStats: shimSenderReceiverGetStats,
    shimAddTrackRemoveTrackWithNative: shimAddTrackRemoveTrackWithNative,
    shimAddTrackRemoveTrack: shimAddTrackRemoveTrack,
    shimPeerConnection: shimPeerConnection$2,
    fixNegotiationNeeded: fixNegotiationNeeded,
    shimGetUserMedia: shimGetUserMedia$3,
    shimGetDisplayMedia: shimGetDisplayMedia$2,
  })

  /*
   *  Copyright (c) 2018 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */
  // Edge does not like
  // 1) stun: filtered after 14393 unless ?transport=udp is present
  // 2) turn: that does not have all of turn:host:port?transport=udp
  // 3) turn: with ipv6 addresses
  // 4) turn: occurring muliple times
  function filterIceServers$1(iceServers, edgeVersion) {
    let hasTurn = false
    iceServers = JSON.parse(JSON.stringify(iceServers))
    return iceServers.filter((server) => {
      if (server && (server.urls || server.url)) {
        let urls = server.urls || server.url
        if (server.url && !server.urls) {
          deprecated('RTCIceServer.url', 'RTCIceServer.urls')
        }
        const isString = typeof urls === 'string'
        if (isString) {
          urls = [urls]
        }
        urls = urls.filter((url) => {
          // filter STUN unconditionally.
          if (url.indexOf('stun:') === 0) {
            return false
          }

          const validTurn =
            url.startsWith('turn') && !url.startsWith('turn:[') && url.includes('transport=udp')
          if (validTurn && !hasTurn) {
            hasTurn = true
            return true
          }
          return validTurn && !hasTurn
        })

        delete server.url
        server.urls = isString ? urls[0] : urls
        return !!urls.length
      }
    })
  }

  function createCommonjsModule(fn) {
    var module = { exports: {} }
    return fn(module, module.exports), module.exports
  }

  /* eslint-env node */

  var sdp = createCommonjsModule(function (module) {
    // SDP helpers.
    var SDPUtils = {}

    // Generate an alphanumeric identifier for cname or mids.
    // TODO: use UUIDs instead? https://gist.github.com/jed/982883
    SDPUtils.generateIdentifier = function () {
      return Math.random().toString(36).substr(2, 10)
    }

    // The RTCP CNAME used by all peerconnections from the same JS.
    SDPUtils.localCName = SDPUtils.generateIdentifier()

    // Splits SDP into lines, dealing with both CRLF and LF.
    SDPUtils.splitLines = function (blob) {
      return blob
        .trim()
        .split('\n')
        .map(function (line) {
          return line.trim()
        })
    }
    // Splits SDP into sessionpart and mediasections. Ensures CRLF.
    SDPUtils.splitSections = function (blob) {
      var parts = blob.split('\nm=')
      return parts.map(function (part, index) {
        return (index > 0 ? 'm=' + part : part).trim() + '\r\n'
      })
    }

    // returns the session description.
    SDPUtils.getDescription = function (blob) {
      var sections = SDPUtils.splitSections(blob)
      return sections && sections[0]
    }

    // returns the individual media sections.
    SDPUtils.getMediaSections = function (blob) {
      var sections = SDPUtils.splitSections(blob)
      sections.shift()
      return sections
    }

    // Returns lines that start with a certain prefix.
    SDPUtils.matchPrefix = function (blob, prefix) {
      return SDPUtils.splitLines(blob).filter(function (line) {
        return line.indexOf(prefix) === 0
      })
    }

    // Parses an ICE candidate line. Sample input:
    // candidate:702786350 2 udp 41819902 8.8.8.8 60769 typ relay raddr 8.8.8.8
    // rport 55996"
    SDPUtils.parseCandidate = function (line) {
      var parts
      // Parse both variants.
      if (line.indexOf('a=candidate:') === 0) {
        parts = line.substring(12).split(' ')
      } else {
        parts = line.substring(10).split(' ')
      }

      var candidate = {
        foundation: parts[0],
        component: parseInt(parts[1], 10),
        protocol: parts[2].toLowerCase(),
        priority: parseInt(parts[3], 10),
        ip: parts[4],
        address: parts[4], // address is an alias for ip.
        port: parseInt(parts[5], 10),
        // skip parts[6] == 'typ'
        type: parts[7],
      }

      for (var i = 8; i < parts.length; i += 2) {
        switch (parts[i]) {
          case 'raddr':
            candidate.relatedAddress = parts[i + 1]
            break
          case 'rport':
            candidate.relatedPort = parseInt(parts[i + 1], 10)
            break
          case 'tcptype':
            candidate.tcpType = parts[i + 1]
            break
          case 'ufrag':
            candidate.ufrag = parts[i + 1] // for backward compability.
            candidate.usernameFragment = parts[i + 1]
            break
          default: // extension handling, in particular ufrag
            candidate[parts[i]] = parts[i + 1]
            break
        }
      }
      return candidate
    }

    // Translates a candidate object into SDP candidate attribute.
    SDPUtils.writeCandidate = function (candidate) {
      var sdp = []
      sdp.push(candidate.foundation)
      sdp.push(candidate.component)
      sdp.push(candidate.protocol.toUpperCase())
      sdp.push(candidate.priority)
      sdp.push(candidate.address || candidate.ip)
      sdp.push(candidate.port)

      var type = candidate.type
      sdp.push('typ')
      sdp.push(type)
      if (type !== 'host' && candidate.relatedAddress && candidate.relatedPort) {
        sdp.push('raddr')
        sdp.push(candidate.relatedAddress)
        sdp.push('rport')
        sdp.push(candidate.relatedPort)
      }
      if (candidate.tcpType && candidate.protocol.toLowerCase() === 'tcp') {
        sdp.push('tcptype')
        sdp.push(candidate.tcpType)
      }
      if (candidate.usernameFragment || candidate.ufrag) {
        sdp.push('ufrag')
        sdp.push(candidate.usernameFragment || candidate.ufrag)
      }
      return 'candidate:' + sdp.join(' ')
    }

    // Parses an ice-options line, returns an array of option tags.
    // a=ice-options:foo bar
    SDPUtils.parseIceOptions = function (line) {
      return line.substr(14).split(' ')
    }

    // Parses an rtpmap line, returns RTCRtpCoddecParameters. Sample input:
    // a=rtpmap:111 opus/48000/2
    SDPUtils.parseRtpMap = function (line) {
      var parts = line.substr(9).split(' ')
      var parsed = {
        payloadType: parseInt(parts.shift(), 10), // was: id
      }

      parts = parts[0].split('/')

      parsed.name = parts[0]
      parsed.clockRate = parseInt(parts[1], 10) // was: clockrate
      parsed.channels = parts.length === 3 ? parseInt(parts[2], 10) : 1
      // legacy alias, got renamed back to channels in ORTC.
      parsed.numChannels = parsed.channels
      return parsed
    }

    // Generate an a=rtpmap line from RTCRtpCodecCapability or
    // RTCRtpCodecParameters.
    SDPUtils.writeRtpMap = function (codec) {
      var pt = codec.payloadType
      if (codec.preferredPayloadType !== undefined) {
        pt = codec.preferredPayloadType
      }
      var channels = codec.channels || codec.numChannels || 1
      return (
        'a=rtpmap:' +
        pt +
        ' ' +
        codec.name +
        '/' +
        codec.clockRate +
        (channels !== 1 ? '/' + channels : '') +
        '\r\n'
      )
    }

    // Parses an a=extmap line (headerextension from RFC 5285). Sample input:
    // a=extmap:2 urn:ietf:params:rtp-hdrext:toffset
    // a=extmap:2/sendonly urn:ietf:params:rtp-hdrext:toffset
    SDPUtils.parseExtmap = function (line) {
      var parts = line.substr(9).split(' ')
      return {
        id: parseInt(parts[0], 10),
        direction: parts[0].indexOf('/') > 0 ? parts[0].split('/')[1] : 'sendrecv',
        uri: parts[1],
      }
    }

    // Generates a=extmap line from RTCRtpHeaderExtensionParameters or
    // RTCRtpHeaderExtension.
    SDPUtils.writeExtmap = function (headerExtension) {
      return (
        'a=extmap:' +
        (headerExtension.id || headerExtension.preferredId) +
        (headerExtension.direction && headerExtension.direction !== 'sendrecv'
          ? '/' + headerExtension.direction
          : '') +
        ' ' +
        headerExtension.uri +
        '\r\n'
      )
    }

    // Parses an ftmp line, returns dictionary. Sample input:
    // a=fmtp:96 vbr=on;cng=on
    // Also deals with vbr=on; cng=on
    SDPUtils.parseFmtp = function (line) {
      var parsed = {}
      var kv
      var parts = line.substr(line.indexOf(' ') + 1).split(';')
      for (var j = 0; j < parts.length; j++) {
        kv = parts[j].trim().split('=')
        parsed[kv[0].trim()] = kv[1]
      }
      return parsed
    }

    // Generates an a=ftmp line from RTCRtpCodecCapability or RTCRtpCodecParameters.
    SDPUtils.writeFmtp = function (codec) {
      var line = ''
      var pt = codec.payloadType
      if (codec.preferredPayloadType !== undefined) {
        pt = codec.preferredPayloadType
      }
      if (codec.parameters && Object.keys(codec.parameters).length) {
        var params = []
        Object.keys(codec.parameters).forEach(function (param) {
          if (codec.parameters[param]) {
            params.push(param + '=' + codec.parameters[param])
          } else {
            params.push(param)
          }
        })
        line += 'a=fmtp:' + pt + ' ' + params.join(';') + '\r\n'
      }
      return line
    }

    // Parses an rtcp-fb line, returns RTCPRtcpFeedback object. Sample input:
    // a=rtcp-fb:98 nack rpsi
    SDPUtils.parseRtcpFb = function (line) {
      var parts = line.substr(line.indexOf(' ') + 1).split(' ')
      return {
        type: parts.shift(),
        parameter: parts.join(' '),
      }
    }
    // Generate a=rtcp-fb lines from RTCRtpCodecCapability or RTCRtpCodecParameters.
    SDPUtils.writeRtcpFb = function (codec) {
      var lines = ''
      var pt = codec.payloadType
      if (codec.preferredPayloadType !== undefined) {
        pt = codec.preferredPayloadType
      }
      if (codec.rtcpFeedback && codec.rtcpFeedback.length) {
        // FIXME: special handling for trr-int?
        codec.rtcpFeedback.forEach(function (fb) {
          lines +=
            'a=rtcp-fb:' +
            pt +
            ' ' +
            fb.type +
            (fb.parameter && fb.parameter.length ? ' ' + fb.parameter : '') +
            '\r\n'
        })
      }
      return lines
    }

    // Parses an RFC 5576 ssrc media attribute. Sample input:
    // a=ssrc:3735928559 cname:something
    SDPUtils.parseSsrcMedia = function (line) {
      var sp = line.indexOf(' ')
      var parts = {
        ssrc: parseInt(line.substr(7, sp - 7), 10),
      }
      var colon = line.indexOf(':', sp)
      if (colon > -1) {
        parts.attribute = line.substr(sp + 1, colon - sp - 1)
        parts.value = line.substr(colon + 1)
      } else {
        parts.attribute = line.substr(sp + 1)
      }
      return parts
    }

    SDPUtils.parseSsrcGroup = function (line) {
      var parts = line.substr(13).split(' ')
      return {
        semantics: parts.shift(),
        ssrcs: parts.map(function (ssrc) {
          return parseInt(ssrc, 10)
        }),
      }
    }

    // Extracts the MID (RFC 5888) from a media section.
    // returns the MID or undefined if no mid line was found.
    SDPUtils.getMid = function (mediaSection) {
      var mid = SDPUtils.matchPrefix(mediaSection, 'a=mid:')[0]
      if (mid) {
        return mid.substr(6)
      }
    }

    SDPUtils.parseFingerprint = function (line) {
      var parts = line.substr(14).split(' ')
      return {
        algorithm: parts[0].toLowerCase(), // algorithm is case-sensitive in Edge.
        value: parts[1],
      }
    }

    // Extracts DTLS parameters from SDP media section or sessionpart.
    // FIXME: for consistency with other functions this should only
    //   get the fingerprint line as input. See also getIceParameters.
    SDPUtils.getDtlsParameters = function (mediaSection, sessionpart) {
      var lines = SDPUtils.matchPrefix(mediaSection + sessionpart, 'a=fingerprint:')
      // Note: a=setup line is ignored since we use the 'auto' role.
      // Note2: 'algorithm' is not case sensitive except in Edge.
      return {
        role: 'auto',
        fingerprints: lines.map(SDPUtils.parseFingerprint),
      }
    }

    // Serializes DTLS parameters to SDP.
    SDPUtils.writeDtlsParameters = function (params, setupType) {
      var sdp = 'a=setup:' + setupType + '\r\n'
      params.fingerprints.forEach(function (fp) {
        sdp += 'a=fingerprint:' + fp.algorithm + ' ' + fp.value + '\r\n'
      })
      return sdp
    }

    // Parses a=crypto lines into
    //   https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#dictionary-rtcsrtpsdesparameters-members
    SDPUtils.parseCryptoLine = function (line) {
      var parts = line.substr(9).split(' ')
      return {
        tag: parseInt(parts[0], 10),
        cryptoSuite: parts[1],
        keyParams: parts[2],
        sessionParams: parts.slice(3),
      }
    }

    SDPUtils.writeCryptoLine = function (parameters) {
      return (
        'a=crypto:' +
        parameters.tag +
        ' ' +
        parameters.cryptoSuite +
        ' ' +
        (typeof parameters.keyParams === 'object'
          ? SDPUtils.writeCryptoKeyParams(parameters.keyParams)
          : parameters.keyParams) +
        (parameters.sessionParams ? ' ' + parameters.sessionParams.join(' ') : '') +
        '\r\n'
      )
    }

    // Parses the crypto key parameters into
    //   https://rawgit.com/aboba/edgertc/master/msortc-rs4.html#rtcsrtpkeyparam*
    SDPUtils.parseCryptoKeyParams = function (keyParams) {
      if (keyParams.indexOf('inline:') !== 0) {
        return null
      }
      var parts = keyParams.substr(7).split('|')
      return {
        keyMethod: 'inline',
        keySalt: parts[0],
        lifeTime: parts[1],
        mkiValue: parts[2] ? parts[2].split(':')[0] : undefined,
        mkiLength: parts[2] ? parts[2].split(':')[1] : undefined,
      }
    }

    SDPUtils.writeCryptoKeyParams = function (keyParams) {
      return (
        keyParams.keyMethod +
        ':' +
        keyParams.keySalt +
        (keyParams.lifeTime ? '|' + keyParams.lifeTime : '') +
        (keyParams.mkiValue && keyParams.mkiLength
          ? '|' + keyParams.mkiValue + ':' + keyParams.mkiLength
          : '')
      )
    }

    // Extracts all SDES paramters.
    SDPUtils.getCryptoParameters = function (mediaSection, sessionpart) {
      var lines = SDPUtils.matchPrefix(mediaSection + sessionpart, 'a=crypto:')
      return lines.map(SDPUtils.parseCryptoLine)
    }

    // Parses ICE information from SDP media section or sessionpart.
    // FIXME: for consistency with other functions this should only
    //   get the ice-ufrag and ice-pwd lines as input.
    SDPUtils.getIceParameters = function (mediaSection, sessionpart) {
      var ufrag = SDPUtils.matchPrefix(mediaSection + sessionpart, 'a=ice-ufrag:')[0]
      var pwd = SDPUtils.matchPrefix(mediaSection + sessionpart, 'a=ice-pwd:')[0]
      if (!(ufrag && pwd)) {
        return null
      }
      return {
        usernameFragment: ufrag.substr(12),
        password: pwd.substr(10),
      }
    }

    // Serializes ICE parameters to SDP.
    SDPUtils.writeIceParameters = function (params) {
      return (
        'a=ice-ufrag:' + params.usernameFragment + '\r\n' + 'a=ice-pwd:' + params.password + '\r\n'
      )
    }

    // Parses the SDP media section and returns RTCRtpParameters.
    SDPUtils.parseRtpParameters = function (mediaSection) {
      var description = {
        codecs: [],
        headerExtensions: [],
        fecMechanisms: [],
        rtcp: [],
      }
      var lines = SDPUtils.splitLines(mediaSection)
      var mline = lines[0].split(' ')
      for (var i = 3; i < mline.length; i++) {
        // find all codecs from mline[3..]
        var pt = mline[i]
        var rtpmapline = SDPUtils.matchPrefix(mediaSection, 'a=rtpmap:' + pt + ' ')[0]
        if (rtpmapline) {
          var codec = SDPUtils.parseRtpMap(rtpmapline)
          var fmtps = SDPUtils.matchPrefix(mediaSection, 'a=fmtp:' + pt + ' ')
          // Only the first a=fmtp:<pt> is considered.
          codec.parameters = fmtps.length ? SDPUtils.parseFmtp(fmtps[0]) : {}
          codec.rtcpFeedback = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-fb:' + pt + ' ').map(
            SDPUtils.parseRtcpFb
          )
          description.codecs.push(codec)
          // parse FEC mechanisms from rtpmap lines.
          switch (codec.name.toUpperCase()) {
            case 'RED':
            case 'ULPFEC':
              description.fecMechanisms.push(codec.name.toUpperCase())
              break
          }
        }
      }
      SDPUtils.matchPrefix(mediaSection, 'a=extmap:').forEach(function (line) {
        description.headerExtensions.push(SDPUtils.parseExtmap(line))
      })
      // FIXME: parse rtcp.
      return description
    }

    // Generates parts of the SDP media section describing the capabilities /
    // parameters.
    SDPUtils.writeRtpDescription = function (kind, caps) {
      var sdp = ''

      // Build the mline.
      sdp += 'm=' + kind + ' '
      sdp += caps.codecs.length > 0 ? '9' : '0' // reject if no codecs.
      sdp += ' UDP/TLS/RTP/SAVPF '
      sdp +=
        caps.codecs
          .map(function (codec) {
            if (codec.preferredPayloadType !== undefined) {
              return codec.preferredPayloadType
            }
            return codec.payloadType
          })
          .join(' ') + '\r\n'

      sdp += 'c=IN IP4 0.0.0.0\r\n'
      sdp += 'a=rtcp:9 IN IP4 0.0.0.0\r\n'

      // Add a=rtpmap lines for each codec. Also fmtp and rtcp-fb.
      caps.codecs.forEach(function (codec) {
        sdp += SDPUtils.writeRtpMap(codec)
        sdp += SDPUtils.writeFmtp(codec)
        sdp += SDPUtils.writeRtcpFb(codec)
      })
      var maxptime = 0
      caps.codecs.forEach(function (codec) {
        if (codec.maxptime > maxptime) {
          maxptime = codec.maxptime
        }
      })
      if (maxptime > 0) {
        sdp += 'a=maxptime:' + maxptime + '\r\n'
      }
      sdp += 'a=rtcp-mux\r\n'

      if (caps.headerExtensions) {
        caps.headerExtensions.forEach(function (extension) {
          sdp += SDPUtils.writeExtmap(extension)
        })
      }
      // FIXME: write fecMechanisms.
      return sdp
    }

    // Parses the SDP media section and returns an array of
    // RTCRtpEncodingParameters.
    SDPUtils.parseRtpEncodingParameters = function (mediaSection) {
      var encodingParameters = []
      var description = SDPUtils.parseRtpParameters(mediaSection)
      var hasRed = description.fecMechanisms.indexOf('RED') !== -1
      var hasUlpfec = description.fecMechanisms.indexOf('ULPFEC') !== -1

      // filter a=ssrc:... cname:, ignore PlanB-msid
      var ssrcs = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
        .map(function (line) {
          return SDPUtils.parseSsrcMedia(line)
        })
        .filter(function (parts) {
          return parts.attribute === 'cname'
        })
      var primarySsrc = ssrcs.length > 0 && ssrcs[0].ssrc
      var secondarySsrc

      var flows = SDPUtils.matchPrefix(mediaSection, 'a=ssrc-group:FID').map(function (line) {
        var parts = line.substr(17).split(' ')
        return parts.map(function (part) {
          return parseInt(part, 10)
        })
      })
      if (flows.length > 0 && flows[0].length > 1 && flows[0][0] === primarySsrc) {
        secondarySsrc = flows[0][1]
      }

      description.codecs.forEach(function (codec) {
        if (codec.name.toUpperCase() === 'RTX' && codec.parameters.apt) {
          var encParam = {
            ssrc: primarySsrc,
            codecPayloadType: parseInt(codec.parameters.apt, 10),
          }
          if (primarySsrc && secondarySsrc) {
            encParam.rtx = { ssrc: secondarySsrc }
          }
          encodingParameters.push(encParam)
          if (hasRed) {
            encParam = JSON.parse(JSON.stringify(encParam))
            encParam.fec = {
              ssrc: primarySsrc,
              mechanism: hasUlpfec ? 'red+ulpfec' : 'red',
            }
            encodingParameters.push(encParam)
          }
        }
      })
      if (encodingParameters.length === 0 && primarySsrc) {
        encodingParameters.push({
          ssrc: primarySsrc,
        })
      }

      // we support both b=AS and b=TIAS but interpret AS as TIAS.
      var bandwidth = SDPUtils.matchPrefix(mediaSection, 'b=')
      if (bandwidth.length) {
        if (bandwidth[0].indexOf('b=TIAS:') === 0) {
          bandwidth = parseInt(bandwidth[0].substr(7), 10)
        } else if (bandwidth[0].indexOf('b=AS:') === 0) {
          // use formula from JSEP to convert b=AS to TIAS value.
          bandwidth = parseInt(bandwidth[0].substr(5), 10) * 1000 * 0.95 - 50 * 40 * 8
        } else {
          bandwidth = undefined
        }
        encodingParameters.forEach(function (params) {
          params.maxBitrate = bandwidth
        })
      }
      return encodingParameters
    }

    // parses http://draft.ortc.org/#rtcrtcpparameters*
    SDPUtils.parseRtcpParameters = function (mediaSection) {
      var rtcpParameters = {}

      // Gets the first SSRC. Note tha with RTX there might be multiple
      // SSRCs.
      var remoteSsrc = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
        .map(function (line) {
          return SDPUtils.parseSsrcMedia(line)
        })
        .filter(function (obj) {
          return obj.attribute === 'cname'
        })[0]
      if (remoteSsrc) {
        rtcpParameters.cname = remoteSsrc.value
        rtcpParameters.ssrc = remoteSsrc.ssrc
      }

      // Edge uses the compound attribute instead of reducedSize
      // compound is !reducedSize
      var rsize = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-rsize')
      rtcpParameters.reducedSize = rsize.length > 0
      rtcpParameters.compound = rsize.length === 0

      // parses the rtcp-mux attrіbute.
      // Note that Edge does not support unmuxed RTCP.
      var mux = SDPUtils.matchPrefix(mediaSection, 'a=rtcp-mux')
      rtcpParameters.mux = mux.length > 0

      return rtcpParameters
    }

    // parses either a=msid: or a=ssrc:... msid lines and returns
    // the id of the MediaStream and MediaStreamTrack.
    SDPUtils.parseMsid = function (mediaSection) {
      var parts
      var spec = SDPUtils.matchPrefix(mediaSection, 'a=msid:')
      if (spec.length === 1) {
        parts = spec[0].substr(7).split(' ')
        return { stream: parts[0], track: parts[1] }
      }
      var planB = SDPUtils.matchPrefix(mediaSection, 'a=ssrc:')
        .map(function (line) {
          return SDPUtils.parseSsrcMedia(line)
        })
        .filter(function (msidParts) {
          return msidParts.attribute === 'msid'
        })
      if (planB.length > 0) {
        parts = planB[0].value.split(' ')
        return { stream: parts[0], track: parts[1] }
      }
    }

    // SCTP
    // parses draft-ietf-mmusic-sctp-sdp-26 first and falls back
    // to draft-ietf-mmusic-sctp-sdp-05
    SDPUtils.parseSctpDescription = function (mediaSection) {
      var mline = SDPUtils.parseMLine(mediaSection)
      var maxSizeLine = SDPUtils.matchPrefix(mediaSection, 'a=max-message-size:')
      var maxMessageSize
      if (maxSizeLine.length > 0) {
        maxMessageSize = parseInt(maxSizeLine[0].substr(19), 10)
      }
      if (isNaN(maxMessageSize)) {
        maxMessageSize = 65536
      }
      var sctpPort = SDPUtils.matchPrefix(mediaSection, 'a=sctp-port:')
      if (sctpPort.length > 0) {
        return {
          port: parseInt(sctpPort[0].substr(12), 10),
          protocol: mline.fmt,
          maxMessageSize: maxMessageSize,
        }
      }
      var sctpMapLines = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:')
      if (sctpMapLines.length > 0) {
        var parts = SDPUtils.matchPrefix(mediaSection, 'a=sctpmap:')[0].substr(10).split(' ')
        return {
          port: parseInt(parts[0], 10),
          protocol: parts[1],
          maxMessageSize: maxMessageSize,
        }
      }
    }

    // SCTP
    // outputs the draft-ietf-mmusic-sctp-sdp-26 version that all browsers
    // support by now receiving in this format, unless we originally parsed
    // as the draft-ietf-mmusic-sctp-sdp-05 format (indicated by the m-line
    // protocol of DTLS/SCTP -- without UDP/ or TCP/)
    SDPUtils.writeSctpDescription = function (media, sctp) {
      var output = []
      if (media.protocol !== 'DTLS/SCTP') {
        output = [
          'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.protocol + '\r\n',
          'c=IN IP4 0.0.0.0\r\n',
          'a=sctp-port:' + sctp.port + '\r\n',
        ]
      } else {
        output = [
          'm=' + media.kind + ' 9 ' + media.protocol + ' ' + sctp.port + '\r\n',
          'c=IN IP4 0.0.0.0\r\n',
          'a=sctpmap:' + sctp.port + ' ' + sctp.protocol + ' 65535\r\n',
        ]
      }
      if (sctp.maxMessageSize !== undefined) {
        output.push('a=max-message-size:' + sctp.maxMessageSize + '\r\n')
      }
      return output.join('')
    }

    // Generate a session ID for SDP.
    // https://tools.ietf.org/html/draft-ietf-rtcweb-jsep-20#section-5.2.1
    // recommends using a cryptographically random +ve 64-bit value
    // but right now this should be acceptable and within the right range
    SDPUtils.generateSessionId = function () {
      return Math.random().toString().substr(2, 21)
    }

    // Write boilder plate for start of SDP
    // sessId argument is optional - if not supplied it will
    // be generated randomly
    // sessVersion is optional and defaults to 2
    // sessUser is optional and defaults to 'thisisadapterortc'
    SDPUtils.writeSessionBoilerplate = function (sessId, sessVer, sessUser) {
      var sessionId
      var version = sessVer !== undefined ? sessVer : 2
      if (sessId) {
        sessionId = sessId
      } else {
        sessionId = SDPUtils.generateSessionId()
      }
      var user = sessUser || 'thisisadapterortc'
      // FIXME: sess-id should be an NTP timestamp.
      return (
        'v=0\r\n' +
        'o=' +
        user +
        ' ' +
        sessionId +
        ' ' +
        version +
        ' IN IP4 127.0.0.1\r\n' +
        's=-\r\n' +
        't=0 0\r\n'
      )
    }

    SDPUtils.writeMediaSection = function (transceiver, caps, type, stream) {
      var sdp = SDPUtils.writeRtpDescription(transceiver.kind, caps)

      // Map ICE parameters (ufrag, pwd) to SDP.
      sdp += SDPUtils.writeIceParameters(transceiver.iceGatherer.getLocalParameters())

      // Map DTLS parameters to SDP.
      sdp += SDPUtils.writeDtlsParameters(
        transceiver.dtlsTransport.getLocalParameters(),
        type === 'offer' ? 'actpass' : 'active'
      )

      sdp += 'a=mid:' + transceiver.mid + '\r\n'

      if (transceiver.direction) {
        sdp += 'a=' + transceiver.direction + '\r\n'
      } else if (transceiver.rtpSender && transceiver.rtpReceiver) {
        sdp += 'a=sendrecv\r\n'
      } else if (transceiver.rtpSender) {
        sdp += 'a=sendonly\r\n'
      } else if (transceiver.rtpReceiver) {
        sdp += 'a=recvonly\r\n'
      } else {
        sdp += 'a=inactive\r\n'
      }

      if (transceiver.rtpSender) {
        // spec.
        var msid = 'msid:' + stream.id + ' ' + transceiver.rtpSender.track.id + '\r\n'
        sdp += 'a=' + msid

        // for Chrome.
        sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc + ' ' + msid
        if (transceiver.sendEncodingParameters[0].rtx) {
          sdp += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc + ' ' + msid
          sdp +=
            'a=ssrc-group:FID ' +
            transceiver.sendEncodingParameters[0].ssrc +
            ' ' +
            transceiver.sendEncodingParameters[0].rtx.ssrc +
            '\r\n'
        }
      }
      // FIXME: this should be written by writeRtpDescription.
      sdp +=
        'a=ssrc:' +
        transceiver.sendEncodingParameters[0].ssrc +
        ' cname:' +
        SDPUtils.localCName +
        '\r\n'
      if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
        sdp +=
          'a=ssrc:' +
          transceiver.sendEncodingParameters[0].rtx.ssrc +
          ' cname:' +
          SDPUtils.localCName +
          '\r\n'
      }
      return sdp
    }

    // Gets the direction from the mediaSection or the sessionpart.
    SDPUtils.getDirection = function (mediaSection, sessionpart) {
      // Look for sendrecv, sendonly, recvonly, inactive, default to sendrecv.
      var lines = SDPUtils.splitLines(mediaSection)
      for (var i = 0; i < lines.length; i++) {
        switch (lines[i]) {
          case 'a=sendrecv':
          case 'a=sendonly':
          case 'a=recvonly':
          case 'a=inactive':
            return lines[i].substr(2)
          // FIXME: What should happen here?
        }
      }
      if (sessionpart) {
        return SDPUtils.getDirection(sessionpart)
      }
      return 'sendrecv'
    }

    SDPUtils.getKind = function (mediaSection) {
      var lines = SDPUtils.splitLines(mediaSection)
      var mline = lines[0].split(' ')
      return mline[0].substr(2)
    }

    SDPUtils.isRejected = function (mediaSection) {
      return mediaSection.split(' ', 2)[1] === '0'
    }

    SDPUtils.parseMLine = function (mediaSection) {
      var lines = SDPUtils.splitLines(mediaSection)
      var parts = lines[0].substr(2).split(' ')
      return {
        kind: parts[0],
        port: parseInt(parts[1], 10),
        protocol: parts[2],
        fmt: parts.slice(3).join(' '),
      }
    }

    SDPUtils.parseOLine = function (mediaSection) {
      var line = SDPUtils.matchPrefix(mediaSection, 'o=')[0]
      var parts = line.substr(2).split(' ')
      return {
        username: parts[0],
        sessionId: parts[1],
        sessionVersion: parseInt(parts[2], 10),
        netType: parts[3],
        addressType: parts[4],
        address: parts[5],
      }
    }

    // a very naive interpretation of a valid SDP.
    SDPUtils.isValidSDP = function (blob) {
      if (typeof blob !== 'string' || blob.length === 0) {
        return false
      }
      var lines = SDPUtils.splitLines(blob)
      for (var i = 0; i < lines.length; i++) {
        if (lines[i].length < 2 || lines[i].charAt(1) !== '=') {
          return false
        }
        // TODO: check the modifier a bit more.
      }
      return true
    }

    // Expose public methods.
    {
      module.exports = SDPUtils
    }
  })

  /*
   *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function fixStatsType(stat) {
    return (
      {
        inboundrtp: 'inbound-rtp',
        outboundrtp: 'outbound-rtp',
        candidatepair: 'candidate-pair',
        localcandidate: 'local-candidate',
        remotecandidate: 'remote-candidate',
      }[stat.type] || stat.type
    )
  }

  function writeMediaSection(transceiver, caps, type, stream, dtlsRole) {
    var sdp$1 = sdp.writeRtpDescription(transceiver.kind, caps)

    // Map ICE parameters (ufrag, pwd) to SDP.
    sdp$1 += sdp.writeIceParameters(transceiver.iceGatherer.getLocalParameters())

    // Map DTLS parameters to SDP.
    sdp$1 += sdp.writeDtlsParameters(
      transceiver.dtlsTransport.getLocalParameters(),
      type === 'offer' ? 'actpass' : dtlsRole || 'active'
    )

    sdp$1 += 'a=mid:' + transceiver.mid + '\r\n'

    if (transceiver.rtpSender && transceiver.rtpReceiver) {
      sdp$1 += 'a=sendrecv\r\n'
    } else if (transceiver.rtpSender) {
      sdp$1 += 'a=sendonly\r\n'
    } else if (transceiver.rtpReceiver) {
      sdp$1 += 'a=recvonly\r\n'
    } else {
      sdp$1 += 'a=inactive\r\n'
    }

    if (transceiver.rtpSender) {
      var trackId = transceiver.rtpSender._initialTrackId || transceiver.rtpSender.track.id
      transceiver.rtpSender._initialTrackId = trackId
      // spec.
      var msid = 'msid:' + (stream ? stream.id : '-') + ' ' + trackId + '\r\n'
      sdp$1 += 'a=' + msid
      // for Chrome. Legacy should no longer be required.
      sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc + ' ' + msid

      // RTX
      if (transceiver.sendEncodingParameters[0].rtx) {
        sdp$1 += 'a=ssrc:' + transceiver.sendEncodingParameters[0].rtx.ssrc + ' ' + msid
        sdp$1 +=
          'a=ssrc-group:FID ' +
          transceiver.sendEncodingParameters[0].ssrc +
          ' ' +
          transceiver.sendEncodingParameters[0].rtx.ssrc +
          '\r\n'
      }
    }
    // FIXME: this should be written by writeRtpDescription.
    sdp$1 +=
      'a=ssrc:' + transceiver.sendEncodingParameters[0].ssrc + ' cname:' + sdp.localCName + '\r\n'
    if (transceiver.rtpSender && transceiver.sendEncodingParameters[0].rtx) {
      sdp$1 +=
        'a=ssrc:' +
        transceiver.sendEncodingParameters[0].rtx.ssrc +
        ' cname:' +
        sdp.localCName +
        '\r\n'
    }
    return sdp$1
  }

  // Edge does not like
  // 1) stun: filtered after 14393 unless ?transport=udp is present
  // 2) turn: that does not have all of turn:host:port?transport=udp
  // 3) turn: with ipv6 addresses
  // 4) turn: occurring muliple times
  function filterIceServers(iceServers, edgeVersion) {
    var hasTurn = false
    iceServers = JSON.parse(JSON.stringify(iceServers))
    return iceServers.filter(function (server) {
      if (server && (server.urls || server.url)) {
        var urls = server.urls || server.url
        if (server.url && !server.urls) {
          console.warn('RTCIceServer.url is deprecated! Use urls instead.')
        }
        var isString = typeof urls === 'string'
        if (isString) {
          urls = [urls]
        }
        urls = urls.filter(function (url) {
          var validTurn =
            url.indexOf('turn:') === 0 &&
            url.indexOf('transport=udp') !== -1 &&
            url.indexOf('turn:[') === -1 &&
            !hasTurn

          if (validTurn) {
            hasTurn = true
            return true
          }
          return (
            url.indexOf('stun:') === 0 &&
            edgeVersion >= 14393 &&
            url.indexOf('?transport=udp') === -1
          )
        })

        delete server.url
        server.urls = isString ? urls[0] : urls
        return !!urls.length
      }
    })
  }

  // Determines the intersection of local and remote capabilities.
  function getCommonCapabilities(localCapabilities, remoteCapabilities) {
    var commonCapabilities = {
      codecs: [],
      headerExtensions: [],
      fecMechanisms: [],
    }

    var findCodecByPayloadType = function (pt, codecs) {
      pt = parseInt(pt, 10)
      for (var i = 0; i < codecs.length; i++) {
        if (codecs[i].payloadType === pt || codecs[i].preferredPayloadType === pt) {
          return codecs[i]
        }
      }
    }

    var rtxCapabilityMatches = function (lRtx, rRtx, lCodecs, rCodecs) {
      var lCodec = findCodecByPayloadType(lRtx.parameters.apt, lCodecs)
      var rCodec = findCodecByPayloadType(rRtx.parameters.apt, rCodecs)
      return lCodec && rCodec && lCodec.name.toLowerCase() === rCodec.name.toLowerCase()
    }

    localCapabilities.codecs.forEach(function (lCodec) {
      for (var i = 0; i < remoteCapabilities.codecs.length; i++) {
        var rCodec = remoteCapabilities.codecs[i]
        if (
          lCodec.name.toLowerCase() === rCodec.name.toLowerCase() &&
          lCodec.clockRate === rCodec.clockRate
        ) {
          if (lCodec.name.toLowerCase() === 'rtx' && lCodec.parameters && rCodec.parameters.apt) {
            // for RTX we need to find the local rtx that has a apt
            // which points to the same local codec as the remote one.
            if (
              !rtxCapabilityMatches(
                lCodec,
                rCodec,
                localCapabilities.codecs,
                remoteCapabilities.codecs
              )
            ) {
              continue
            }
          }
          rCodec = JSON.parse(JSON.stringify(rCodec)) // deepcopy
          // number of channels is the highest common number of channels
          rCodec.numChannels = Math.min(lCodec.numChannels, rCodec.numChannels)
          // push rCodec so we reply with offerer payload type
          commonCapabilities.codecs.push(rCodec)

          // determine common feedback mechanisms
          rCodec.rtcpFeedback = rCodec.rtcpFeedback.filter(function (fb) {
            for (var j = 0; j < lCodec.rtcpFeedback.length; j++) {
              if (
                lCodec.rtcpFeedback[j].type === fb.type &&
                lCodec.rtcpFeedback[j].parameter === fb.parameter
              ) {
                return true
              }
            }
            return false
          })
          // FIXME: also need to determine .parameters
          //  see https://github.com/openpeer/ortc/issues/569
          break
        }
      }
    })

    localCapabilities.headerExtensions.forEach(function (lHeaderExtension) {
      for (var i = 0; i < remoteCapabilities.headerExtensions.length; i++) {
        var rHeaderExtension = remoteCapabilities.headerExtensions[i]
        if (lHeaderExtension.uri === rHeaderExtension.uri) {
          commonCapabilities.headerExtensions.push(rHeaderExtension)
          break
        }
      }
    })

    // FIXME: fecMechanisms
    return commonCapabilities
  }

  // is action=setLocalDescription with type allowed in signalingState
  function isActionAllowedInSignalingState(action, type, signalingState) {
    return (
      {
        offer: {
          setLocalDescription: ['stable', 'have-local-offer'],
          setRemoteDescription: ['stable', 'have-remote-offer'],
        },
        answer: {
          setLocalDescription: ['have-remote-offer', 'have-local-pranswer'],
          setRemoteDescription: ['have-local-offer', 'have-remote-pranswer'],
        },
      }[type][action].indexOf(signalingState) !== -1
    )
  }

  function maybeAddCandidate(iceTransport, candidate) {
    // Edge's internal representation adds some fields therefore
    // not all fieldѕ are taken into account.
    var alreadyAdded = iceTransport.getRemoteCandidates().find(function (remoteCandidate) {
      return (
        candidate.foundation === remoteCandidate.foundation &&
        candidate.ip === remoteCandidate.ip &&
        candidate.port === remoteCandidate.port &&
        candidate.priority === remoteCandidate.priority &&
        candidate.protocol === remoteCandidate.protocol &&
        candidate.type === remoteCandidate.type
      )
    })
    if (!alreadyAdded) {
      iceTransport.addRemoteCandidate(candidate)
    }
    return !alreadyAdded
  }

  function makeError(name, description) {
    var e = new Error(description)
    e.name = name
    // legacy error codes from https://heycam.github.io/webidl/#idl-DOMException-error-names
    e.code = {
      NotSupportedError: 9,
      InvalidStateError: 11,
      InvalidAccessError: 15,
      TypeError: undefined,
      OperationError: undefined,
    }[name]
    return e
  }

  var rtcpeerconnection = function (window, edgeVersion) {
    // https://w3c.github.io/mediacapture-main/#mediastream
    // Helper function to add the track to the stream and
    // dispatch the event ourselves.
    function addTrackToStreamAndFireEvent(track, stream) {
      stream.addTrack(track)
      stream.dispatchEvent(new window.MediaStreamTrackEvent('addtrack', { track: track }))
    }

    function removeTrackFromStreamAndFireEvent(track, stream) {
      stream.removeTrack(track)
      stream.dispatchEvent(new window.MediaStreamTrackEvent('removetrack', { track: track }))
    }

    function fireAddTrack(pc, track, receiver, streams) {
      var trackEvent = new Event('track')
      trackEvent.track = track
      trackEvent.receiver = receiver
      trackEvent.transceiver = { receiver: receiver }
      trackEvent.streams = streams
      window.setTimeout(function () {
        pc._dispatchEvent('track', trackEvent)
      })
    }

    var RTCPeerConnection = function (config) {
      var pc = this

      var _eventTarget = document.createDocumentFragment()
      ;['addEventListener', 'removeEventListener', 'dispatchEvent'].forEach(function (method) {
        pc[method] = _eventTarget[method].bind(_eventTarget)
      })

      this.canTrickleIceCandidates = null

      this.needNegotiation = false

      this.localStreams = []
      this.remoteStreams = []

      this._localDescription = null
      this._remoteDescription = null

      this.signalingState = 'stable'
      this.iceConnectionState = 'new'
      this.connectionState = 'new'
      this.iceGatheringState = 'new'

      config = JSON.parse(JSON.stringify(config || {}))

      this.usingBundle = config.bundlePolicy === 'max-bundle'
      if (config.rtcpMuxPolicy === 'negotiate') {
        throw makeError('NotSupportedError', "rtcpMuxPolicy 'negotiate' is not supported")
      } else if (!config.rtcpMuxPolicy) {
        config.rtcpMuxPolicy = 'require'
      }

      switch (config.iceTransportPolicy) {
        case 'all':
        case 'relay':
          break
        default:
          config.iceTransportPolicy = 'all'
          break
      }

      switch (config.bundlePolicy) {
        case 'balanced':
        case 'max-compat':
        case 'max-bundle':
          break
        default:
          config.bundlePolicy = 'balanced'
          break
      }

      config.iceServers = filterIceServers(config.iceServers || [], edgeVersion)

      this._iceGatherers = []
      if (config.iceCandidatePoolSize) {
        for (var i = config.iceCandidatePoolSize; i > 0; i--) {
          this._iceGatherers.push(
            new window.RTCIceGatherer({
              iceServers: config.iceServers,
              gatherPolicy: config.iceTransportPolicy,
            })
          )
        }
      } else {
        config.iceCandidatePoolSize = 0
      }

      this._config = config

      // per-track iceGathers, iceTransports, dtlsTransports, rtpSenders, ...
      // everything that is needed to describe a SDP m-line.
      this.transceivers = []

      this._sdpSessionId = sdp.generateSessionId()
      this._sdpSessionVersion = 0

      this._dtlsRole = undefined // role for a=setup to use in answers.

      this._isClosed = false
    }

    Object.defineProperty(RTCPeerConnection.prototype, 'localDescription', {
      configurable: true,
      get: function () {
        return this._localDescription
      },
    })
    Object.defineProperty(RTCPeerConnection.prototype, 'remoteDescription', {
      configurable: true,
      get: function () {
        return this._remoteDescription
      },
    })

    // set up event handlers on prototype
    RTCPeerConnection.prototype.onicecandidate = null
    RTCPeerConnection.prototype.onaddstream = null
    RTCPeerConnection.prototype.ontrack = null
    RTCPeerConnection.prototype.onremovestream = null
    RTCPeerConnection.prototype.onsignalingstatechange = null
    RTCPeerConnection.prototype.oniceconnectionstatechange = null
    RTCPeerConnection.prototype.onconnectionstatechange = null
    RTCPeerConnection.prototype.onicegatheringstatechange = null
    RTCPeerConnection.prototype.onnegotiationneeded = null
    RTCPeerConnection.prototype.ondatachannel = null

    RTCPeerConnection.prototype._dispatchEvent = function (name, event) {
      if (this._isClosed) {
        return
      }
      this.dispatchEvent(event)
      if (typeof this['on' + name] === 'function') {
        this['on' + name](event)
      }
    }

    RTCPeerConnection.prototype._emitGatheringStateChange = function () {
      var event = new Event('icegatheringstatechange')
      this._dispatchEvent('icegatheringstatechange', event)
    }

    RTCPeerConnection.prototype.getConfiguration = function () {
      return this._config
    }

    RTCPeerConnection.prototype.getLocalStreams = function () {
      return this.localStreams
    }

    RTCPeerConnection.prototype.getRemoteStreams = function () {
      return this.remoteStreams
    }

    // internal helper to create a transceiver object.
    // (which is not yet the same as the WebRTC 1.0 transceiver)
    RTCPeerConnection.prototype._createTransceiver = function (kind, doNotAdd) {
      var hasBundleTransport = this.transceivers.length > 0
      var transceiver = {
        track: null,
        iceGatherer: null,
        iceTransport: null,
        dtlsTransport: null,
        localCapabilities: null,
        remoteCapabilities: null,
        rtpSender: null,
        rtpReceiver: null,
        kind: kind,
        mid: null,
        sendEncodingParameters: null,
        recvEncodingParameters: null,
        stream: null,
        associatedRemoteMediaStreams: [],
        wantReceive: true,
      }
      if (this.usingBundle && hasBundleTransport) {
        transceiver.iceTransport = this.transceivers[0].iceTransport
        transceiver.dtlsTransport = this.transceivers[0].dtlsTransport
      } else {
        var transports = this._createIceAndDtlsTransports()
        transceiver.iceTransport = transports.iceTransport
        transceiver.dtlsTransport = transports.dtlsTransport
      }
      if (!doNotAdd) {
        this.transceivers.push(transceiver)
      }
      return transceiver
    }

    RTCPeerConnection.prototype.addTrack = function (track, stream) {
      if (this._isClosed) {
        throw makeError(
          'InvalidStateError',
          'Attempted to call addTrack on a closed peerconnection.'
        )
      }

      var alreadyExists = this.transceivers.find(function (s) {
        return s.track === track
      })

      if (alreadyExists) {
        throw makeError('InvalidAccessError', 'Track already exists.')
      }

      var transceiver
      for (var i = 0; i < this.transceivers.length; i++) {
        if (!this.transceivers[i].track && this.transceivers[i].kind === track.kind) {
          transceiver = this.transceivers[i]
        }
      }
      if (!transceiver) {
        transceiver = this._createTransceiver(track.kind)
      }

      this._maybeFireNegotiationNeeded()

      if (this.localStreams.indexOf(stream) === -1) {
        this.localStreams.push(stream)
      }

      transceiver.track = track
      transceiver.stream = stream
      transceiver.rtpSender = new window.RTCRtpSender(track, transceiver.dtlsTransport)
      return transceiver.rtpSender
    }

    RTCPeerConnection.prototype.addStream = function (stream) {
      var pc = this
      if (edgeVersion >= 15025) {
        stream.getTracks().forEach(function (track) {
          pc.addTrack(track, stream)
        })
      } else {
        // Clone is necessary for local demos mostly, attaching directly
        // to two different senders does not work (build 10547).
        // Fixed in 15025 (or earlier)
        var clonedStream = stream.clone()
        stream.getTracks().forEach(function (track, idx) {
          var clonedTrack = clonedStream.getTracks()[idx]
          track.addEventListener('enabled', function (event) {
            clonedTrack.enabled = event.enabled
          })
        })
        clonedStream.getTracks().forEach(function (track) {
          pc.addTrack(track, clonedStream)
        })
      }
    }

    RTCPeerConnection.prototype.removeTrack = function (sender) {
      if (this._isClosed) {
        throw makeError(
          'InvalidStateError',
          'Attempted to call removeTrack on a closed peerconnection.'
        )
      }

      if (!(sender instanceof window.RTCRtpSender)) {
        throw new TypeError(
          'Argument 1 of RTCPeerConnection.removeTrack ' +
            'does not implement interface RTCRtpSender.'
        )
      }

      var transceiver = this.transceivers.find(function (t) {
        return t.rtpSender === sender
      })

      if (!transceiver) {
        throw makeError('InvalidAccessError', 'Sender was not created by this connection.')
      }
      var stream = transceiver.stream

      transceiver.rtpSender.stop()
      transceiver.rtpSender = null
      transceiver.track = null
      transceiver.stream = null

      // remove the stream from the set of local streams
      var localStreams = this.transceivers.map(function (t) {
        return t.stream
      })
      if (localStreams.indexOf(stream) === -1 && this.localStreams.indexOf(stream) > -1) {
        this.localStreams.splice(this.localStreams.indexOf(stream), 1)
      }

      this._maybeFireNegotiationNeeded()
    }

    RTCPeerConnection.prototype.removeStream = function (stream) {
      var pc = this
      stream.getTracks().forEach(function (track) {
        var sender = pc.getSenders().find(function (s) {
          return s.track === track
        })
        if (sender) {
          pc.removeTrack(sender)
        }
      })
    }

    RTCPeerConnection.prototype.getSenders = function () {
      return this.transceivers
        .filter(function (transceiver) {
          return !!transceiver.rtpSender
        })
        .map(function (transceiver) {
          return transceiver.rtpSender
        })
    }

    RTCPeerConnection.prototype.getReceivers = function () {
      return this.transceivers
        .filter(function (transceiver) {
          return !!transceiver.rtpReceiver
        })
        .map(function (transceiver) {
          return transceiver.rtpReceiver
        })
    }

    RTCPeerConnection.prototype._createIceGatherer = function (sdpMLineIndex, usingBundle) {
      var pc = this
      if (usingBundle && sdpMLineIndex > 0) {
        return this.transceivers[0].iceGatherer
      } else if (this._iceGatherers.length) {
        return this._iceGatherers.shift()
      }
      var iceGatherer = new window.RTCIceGatherer({
        iceServers: this._config.iceServers,
        gatherPolicy: this._config.iceTransportPolicy,
      })
      Object.defineProperty(iceGatherer, 'state', { value: 'new', writable: true })

      this.transceivers[sdpMLineIndex].bufferedCandidateEvents = []
      this.transceivers[sdpMLineIndex].bufferCandidates = function (event) {
        var end = !event.candidate || Object.keys(event.candidate).length === 0
        // polyfill since RTCIceGatherer.state is not implemented in
        // Edge 10547 yet.
        iceGatherer.state = end ? 'completed' : 'gathering'
        if (pc.transceivers[sdpMLineIndex].bufferedCandidateEvents !== null) {
          pc.transceivers[sdpMLineIndex].bufferedCandidateEvents.push(event)
        }
      }
      iceGatherer.addEventListener(
        'localcandidate',
        this.transceivers[sdpMLineIndex].bufferCandidates
      )
      return iceGatherer
    }

    // start gathering from an RTCIceGatherer.
    RTCPeerConnection.prototype._gather = function (mid, sdpMLineIndex) {
      var pc = this
      var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer
      if (iceGatherer.onlocalcandidate) {
        return
      }
      var bufferedCandidateEvents = this.transceivers[sdpMLineIndex].bufferedCandidateEvents
      this.transceivers[sdpMLineIndex].bufferedCandidateEvents = null
      iceGatherer.removeEventListener(
        'localcandidate',
        this.transceivers[sdpMLineIndex].bufferCandidates
      )
      iceGatherer.onlocalcandidate = function (evt) {
        if (pc.usingBundle && sdpMLineIndex > 0) {
          // if we know that we use bundle we can drop candidates with
          // ѕdpMLineIndex > 0. If we don't do this then our state gets
          // confused since we dispose the extra ice gatherer.
          return
        }
        var event = new Event('icecandidate')
        event.candidate = { sdpMid: mid, sdpMLineIndex: sdpMLineIndex }

        var cand = evt.candidate
        // Edge emits an empty object for RTCIceCandidateComplete‥
        var end = !cand || Object.keys(cand).length === 0
        if (end) {
          // polyfill since RTCIceGatherer.state is not implemented in
          // Edge 10547 yet.
          if (iceGatherer.state === 'new' || iceGatherer.state === 'gathering') {
            iceGatherer.state = 'completed'
          }
        } else {
          if (iceGatherer.state === 'new') {
            iceGatherer.state = 'gathering'
          }
          // RTCIceCandidate doesn't have a component, needs to be added
          cand.component = 1
          // also the usernameFragment. TODO: update SDP to take both variants.
          cand.ufrag = iceGatherer.getLocalParameters().usernameFragment

          var serializedCandidate = sdp.writeCandidate(cand)
          event.candidate = Object.assign(event.candidate, sdp.parseCandidate(serializedCandidate))

          event.candidate.candidate = serializedCandidate
          event.candidate.toJSON = function () {
            return {
              candidate: event.candidate.candidate,
              sdpMid: event.candidate.sdpMid,
              sdpMLineIndex: event.candidate.sdpMLineIndex,
              usernameFragment: event.candidate.usernameFragment,
            }
          }
        }

        // update local description.
        var sections = sdp.getMediaSections(pc._localDescription.sdp)
        if (!end) {
          sections[event.candidate.sdpMLineIndex] += 'a=' + event.candidate.candidate + '\r\n'
        } else {
          sections[event.candidate.sdpMLineIndex] += 'a=end-of-candidates\r\n'
        }
        pc._localDescription.sdp = sdp.getDescription(pc._localDescription.sdp) + sections.join('')
        var complete = pc.transceivers.every(function (transceiver) {
          return transceiver.iceGatherer && transceiver.iceGatherer.state === 'completed'
        })

        if (pc.iceGatheringState !== 'gathering') {
          pc.iceGatheringState = 'gathering'
          pc._emitGatheringStateChange()
        }

        // Emit candidate. Also emit null candidate when all gatherers are
        // complete.
        if (!end) {
          pc._dispatchEvent('icecandidate', event)
        }
        if (complete) {
          pc._dispatchEvent('icecandidate', new Event('icecandidate'))
          pc.iceGatheringState = 'complete'
          pc._emitGatheringStateChange()
        }
      }

      // emit already gathered candidates.
      window.setTimeout(function () {
        bufferedCandidateEvents.forEach(function (e) {
          iceGatherer.onlocalcandidate(e)
        })
      }, 0)
    }

    // Create ICE transport and DTLS transport.
    RTCPeerConnection.prototype._createIceAndDtlsTransports = function () {
      var pc = this
      var iceTransport = new window.RTCIceTransport(null)
      iceTransport.onicestatechange = function () {
        pc._updateIceConnectionState()
        pc._updateConnectionState()
      }

      var dtlsTransport = new window.RTCDtlsTransport(iceTransport)
      dtlsTransport.ondtlsstatechange = function () {
        pc._updateConnectionState()
      }
      dtlsTransport.onerror = function () {
        // onerror does not set state to failed by itself.
        Object.defineProperty(dtlsTransport, 'state', { value: 'failed', writable: true })
        pc._updateConnectionState()
      }

      return {
        iceTransport: iceTransport,
        dtlsTransport: dtlsTransport,
      }
    }

    // Destroy ICE gatherer, ICE transport and DTLS transport.
    // Without triggering the callbacks.
    RTCPeerConnection.prototype._disposeIceAndDtlsTransports = function (sdpMLineIndex) {
      var iceGatherer = this.transceivers[sdpMLineIndex].iceGatherer
      if (iceGatherer) {
        delete iceGatherer.onlocalcandidate
        delete this.transceivers[sdpMLineIndex].iceGatherer
      }
      var iceTransport = this.transceivers[sdpMLineIndex].iceTransport
      if (iceTransport) {
        delete iceTransport.onicestatechange
        delete this.transceivers[sdpMLineIndex].iceTransport
      }
      var dtlsTransport = this.transceivers[sdpMLineIndex].dtlsTransport
      if (dtlsTransport) {
        delete dtlsTransport.ondtlsstatechange
        delete dtlsTransport.onerror
        delete this.transceivers[sdpMLineIndex].dtlsTransport
      }
    }

    // Start the RTP Sender and Receiver for a transceiver.
    RTCPeerConnection.prototype._transceive = function (transceiver, send, recv) {
      var params = getCommonCapabilities(
        transceiver.localCapabilities,
        transceiver.remoteCapabilities
      )
      if (send && transceiver.rtpSender) {
        params.encodings = transceiver.sendEncodingParameters
        params.rtcp = {
          cname: sdp.localCName,
          compound: transceiver.rtcpParameters.compound,
        }
        if (transceiver.recvEncodingParameters.length) {
          params.rtcp.ssrc = transceiver.recvEncodingParameters[0].ssrc
        }
        transceiver.rtpSender.send(params)
      }
      if (recv && transceiver.rtpReceiver && params.codecs.length > 0) {
        // remove RTX field in Edge 14942
        if (
          transceiver.kind === 'video' &&
          transceiver.recvEncodingParameters &&
          edgeVersion < 15019
        ) {
          transceiver.recvEncodingParameters.forEach(function (p) {
            delete p.rtx
          })
        }
        if (transceiver.recvEncodingParameters.length) {
          params.encodings = transceiver.recvEncodingParameters
        } else {
          params.encodings = [{}]
        }
        params.rtcp = {
          compound: transceiver.rtcpParameters.compound,
        }
        if (transceiver.rtcpParameters.cname) {
          params.rtcp.cname = transceiver.rtcpParameters.cname
        }
        if (transceiver.sendEncodingParameters.length) {
          params.rtcp.ssrc = transceiver.sendEncodingParameters[0].ssrc
        }
        transceiver.rtpReceiver.receive(params)
      }
    }

    RTCPeerConnection.prototype.setLocalDescription = function (description) {
      var pc = this

      // Note: pranswer is not supported.
      if (['offer', 'answer'].indexOf(description.type) === -1) {
        return Promise.reject(makeError('TypeError', 'Unsupported type "' + description.type + '"'))
      }

      if (
        !isActionAllowedInSignalingState(
          'setLocalDescription',
          description.type,
          pc.signalingState
        ) ||
        pc._isClosed
      ) {
        return Promise.reject(
          makeError(
            'InvalidStateError',
            'Can not set local ' + description.type + ' in state ' + pc.signalingState
          )
        )
      }

      var sections
      var sessionpart
      if (description.type === 'offer') {
        // VERY limited support for SDP munging. Limited to:
        // * changing the order of codecs
        sections = sdp.splitSections(description.sdp)
        sessionpart = sections.shift()
        sections.forEach(function (mediaSection, sdpMLineIndex) {
          var caps = sdp.parseRtpParameters(mediaSection)
          pc.transceivers[sdpMLineIndex].localCapabilities = caps
        })

        pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
          pc._gather(transceiver.mid, sdpMLineIndex)
        })
      } else if (description.type === 'answer') {
        sections = sdp.splitSections(pc._remoteDescription.sdp)
        sessionpart = sections.shift()
        var isIceLite = sdp.matchPrefix(sessionpart, 'a=ice-lite').length > 0
        sections.forEach(function (mediaSection, sdpMLineIndex) {
          var transceiver = pc.transceivers[sdpMLineIndex]
          var iceGatherer = transceiver.iceGatherer
          var iceTransport = transceiver.iceTransport
          var dtlsTransport = transceiver.dtlsTransport
          var localCapabilities = transceiver.localCapabilities
          var remoteCapabilities = transceiver.remoteCapabilities

          // treat bundle-only as not-rejected.
          var rejected =
            sdp.isRejected(mediaSection) &&
            sdp.matchPrefix(mediaSection, 'a=bundle-only').length === 0

          if (!rejected && !transceiver.rejected) {
            var remoteIceParameters = sdp.getIceParameters(mediaSection, sessionpart)
            var remoteDtlsParameters = sdp.getDtlsParameters(mediaSection, sessionpart)
            if (isIceLite) {
              remoteDtlsParameters.role = 'server'
            }

            if (!pc.usingBundle || sdpMLineIndex === 0) {
              pc._gather(transceiver.mid, sdpMLineIndex)
              if (iceTransport.state === 'new') {
                iceTransport.start(
                  iceGatherer,
                  remoteIceParameters,
                  isIceLite ? 'controlling' : 'controlled'
                )
              }
              if (dtlsTransport.state === 'new') {
                dtlsTransport.start(remoteDtlsParameters)
              }
            }

            // Calculate intersection of capabilities.
            var params = getCommonCapabilities(localCapabilities, remoteCapabilities)

            // Start the RTCRtpSender. The RTCRtpReceiver for this
            // transceiver has already been started in setRemoteDescription.
            pc._transceive(transceiver, params.codecs.length > 0, false)
          }
        })
      }

      pc._localDescription = {
        type: description.type,
        sdp: description.sdp,
      }
      if (description.type === 'offer') {
        pc._updateSignalingState('have-local-offer')
      } else {
        pc._updateSignalingState('stable')
      }

      return Promise.resolve()
    }

    RTCPeerConnection.prototype.setRemoteDescription = function (description) {
      var pc = this

      // Note: pranswer is not supported.
      if (['offer', 'answer'].indexOf(description.type) === -1) {
        return Promise.reject(makeError('TypeError', 'Unsupported type "' + description.type + '"'))
      }

      if (
        !isActionAllowedInSignalingState(
          'setRemoteDescription',
          description.type,
          pc.signalingState
        ) ||
        pc._isClosed
      ) {
        return Promise.reject(
          makeError(
            'InvalidStateError',
            'Can not set remote ' + description.type + ' in state ' + pc.signalingState
          )
        )
      }

      var streams = {}
      pc.remoteStreams.forEach(function (stream) {
        streams[stream.id] = stream
      })
      var receiverList = []
      var sections = sdp.splitSections(description.sdp)
      var sessionpart = sections.shift()
      var isIceLite = sdp.matchPrefix(sessionpart, 'a=ice-lite').length > 0
      var usingBundle = sdp.matchPrefix(sessionpart, 'a=group:BUNDLE ').length > 0
      pc.usingBundle = usingBundle
      var iceOptions = sdp.matchPrefix(sessionpart, 'a=ice-options:')[0]
      if (iceOptions) {
        pc.canTrickleIceCandidates = iceOptions.substr(14).split(' ').indexOf('trickle') >= 0
      } else {
        pc.canTrickleIceCandidates = false
      }

      sections.forEach(function (mediaSection, sdpMLineIndex) {
        var lines = sdp.splitLines(mediaSection)
        var kind = sdp.getKind(mediaSection)
        // treat bundle-only as not-rejected.
        var rejected =
          sdp.isRejected(mediaSection) &&
          sdp.matchPrefix(mediaSection, 'a=bundle-only').length === 0
        var protocol = lines[0].substr(2).split(' ')[2]

        var direction = sdp.getDirection(mediaSection, sessionpart)
        var remoteMsid = sdp.parseMsid(mediaSection)

        var mid = sdp.getMid(mediaSection) || sdp.generateIdentifier()

        // Reject datachannels which are not implemented yet.
        if (
          rejected ||
          (kind === 'application' && (protocol === 'DTLS/SCTP' || protocol === 'UDP/DTLS/SCTP'))
        ) {
          // TODO: this is dangerous in the case where a non-rejected m-line
          //     becomes rejected.
          pc.transceivers[sdpMLineIndex] = {
            mid: mid,
            kind: kind,
            protocol: protocol,
            rejected: true,
          }
          return
        }

        if (
          !rejected &&
          pc.transceivers[sdpMLineIndex] &&
          pc.transceivers[sdpMLineIndex].rejected
        ) {
          // recycle a rejected transceiver.
          pc.transceivers[sdpMLineIndex] = pc._createTransceiver(kind, true)
        }

        var transceiver
        var iceGatherer
        var iceTransport
        var dtlsTransport
        var rtpReceiver
        var sendEncodingParameters
        var recvEncodingParameters
        var localCapabilities

        var track
        // FIXME: ensure the mediaSection has rtcp-mux set.
        var remoteCapabilities = sdp.parseRtpParameters(mediaSection)
        var remoteIceParameters
        var remoteDtlsParameters
        if (!rejected) {
          remoteIceParameters = sdp.getIceParameters(mediaSection, sessionpart)
          remoteDtlsParameters = sdp.getDtlsParameters(mediaSection, sessionpart)
          remoteDtlsParameters.role = 'client'
        }
        recvEncodingParameters = sdp.parseRtpEncodingParameters(mediaSection)

        var rtcpParameters = sdp.parseRtcpParameters(mediaSection)

        var isComplete =
          sdp.matchPrefix(mediaSection, 'a=end-of-candidates', sessionpart).length > 0
        var cands = sdp
          .matchPrefix(mediaSection, 'a=candidate:')
          .map(function (cand) {
            return sdp.parseCandidate(cand)
          })
          .filter(function (cand) {
            return cand.component === 1
          })

        // Check if we can use BUNDLE and dispose transports.
        if (
          (description.type === 'offer' || description.type === 'answer') &&
          !rejected &&
          usingBundle &&
          sdpMLineIndex > 0 &&
          pc.transceivers[sdpMLineIndex]
        ) {
          pc._disposeIceAndDtlsTransports(sdpMLineIndex)
          pc.transceivers[sdpMLineIndex].iceGatherer = pc.transceivers[0].iceGatherer
          pc.transceivers[sdpMLineIndex].iceTransport = pc.transceivers[0].iceTransport
          pc.transceivers[sdpMLineIndex].dtlsTransport = pc.transceivers[0].dtlsTransport
          if (pc.transceivers[sdpMLineIndex].rtpSender) {
            pc.transceivers[sdpMLineIndex].rtpSender.setTransport(pc.transceivers[0].dtlsTransport)
          }
          if (pc.transceivers[sdpMLineIndex].rtpReceiver) {
            pc.transceivers[sdpMLineIndex].rtpReceiver.setTransport(
              pc.transceivers[0].dtlsTransport
            )
          }
        }
        if (description.type === 'offer' && !rejected) {
          transceiver = pc.transceivers[sdpMLineIndex] || pc._createTransceiver(kind)
          transceiver.mid = mid

          if (!transceiver.iceGatherer) {
            transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex, usingBundle)
          }

          if (cands.length && transceiver.iceTransport.state === 'new') {
            if (isComplete && (!usingBundle || sdpMLineIndex === 0)) {
              transceiver.iceTransport.setRemoteCandidates(cands)
            } else {
              cands.forEach(function (candidate) {
                maybeAddCandidate(transceiver.iceTransport, candidate)
              })
            }
          }

          localCapabilities = window.RTCRtpReceiver.getCapabilities(kind)

          // filter RTX until additional stuff needed for RTX is implemented
          // in adapter.js
          if (edgeVersion < 15019) {
            localCapabilities.codecs = localCapabilities.codecs.filter(function (codec) {
              return codec.name !== 'rtx'
            })
          }

          sendEncodingParameters = transceiver.sendEncodingParameters || [
            {
              ssrc: (2 * sdpMLineIndex + 2) * 1001,
            },
          ]

          // TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
          var isNewTrack = false
          if (direction === 'sendrecv' || direction === 'sendonly') {
            isNewTrack = !transceiver.rtpReceiver
            rtpReceiver =
              transceiver.rtpReceiver || new window.RTCRtpReceiver(transceiver.dtlsTransport, kind)

            if (isNewTrack) {
              var stream
              track = rtpReceiver.track
              // FIXME: does not work with Plan B.
              if (remoteMsid && remoteMsid.stream === '-');
              else if (remoteMsid) {
                if (!streams[remoteMsid.stream]) {
                  streams[remoteMsid.stream] = new window.MediaStream()
                  Object.defineProperty(streams[remoteMsid.stream], 'id', {
                    get: function () {
                      return remoteMsid.stream
                    },
                  })
                }
                Object.defineProperty(track, 'id', {
                  get: function () {
                    return remoteMsid.track
                  },
                })
                stream = streams[remoteMsid.stream]
              } else {
                if (!streams.default) {
                  streams.default = new window.MediaStream()
                }
                stream = streams.default
              }
              if (stream) {
                addTrackToStreamAndFireEvent(track, stream)
                transceiver.associatedRemoteMediaStreams.push(stream)
              }
              receiverList.push([track, rtpReceiver, stream])
            }
          } else if (transceiver.rtpReceiver && transceiver.rtpReceiver.track) {
            transceiver.associatedRemoteMediaStreams.forEach(function (s) {
              var nativeTrack = s.getTracks().find(function (t) {
                return t.id === transceiver.rtpReceiver.track.id
              })
              if (nativeTrack) {
                removeTrackFromStreamAndFireEvent(nativeTrack, s)
              }
            })
            transceiver.associatedRemoteMediaStreams = []
          }

          transceiver.localCapabilities = localCapabilities
          transceiver.remoteCapabilities = remoteCapabilities
          transceiver.rtpReceiver = rtpReceiver
          transceiver.rtcpParameters = rtcpParameters
          transceiver.sendEncodingParameters = sendEncodingParameters
          transceiver.recvEncodingParameters = recvEncodingParameters

          // Start the RTCRtpReceiver now. The RTPSender is started in
          // setLocalDescription.
          pc._transceive(pc.transceivers[sdpMLineIndex], false, isNewTrack)
        } else if (description.type === 'answer' && !rejected) {
          transceiver = pc.transceivers[sdpMLineIndex]
          iceGatherer = transceiver.iceGatherer
          iceTransport = transceiver.iceTransport
          dtlsTransport = transceiver.dtlsTransport
          rtpReceiver = transceiver.rtpReceiver
          sendEncodingParameters = transceiver.sendEncodingParameters
          localCapabilities = transceiver.localCapabilities

          pc.transceivers[sdpMLineIndex].recvEncodingParameters = recvEncodingParameters
          pc.transceivers[sdpMLineIndex].remoteCapabilities = remoteCapabilities
          pc.transceivers[sdpMLineIndex].rtcpParameters = rtcpParameters

          if (cands.length && iceTransport.state === 'new') {
            if ((isIceLite || isComplete) && (!usingBundle || sdpMLineIndex === 0)) {
              iceTransport.setRemoteCandidates(cands)
            } else {
              cands.forEach(function (candidate) {
                maybeAddCandidate(transceiver.iceTransport, candidate)
              })
            }
          }

          if (!usingBundle || sdpMLineIndex === 0) {
            if (iceTransport.state === 'new') {
              iceTransport.start(iceGatherer, remoteIceParameters, 'controlling')
            }
            if (dtlsTransport.state === 'new') {
              dtlsTransport.start(remoteDtlsParameters)
            }
          }

          // If the offer contained RTX but the answer did not,
          // remove RTX from sendEncodingParameters.
          var commonCapabilities = getCommonCapabilities(
            transceiver.localCapabilities,
            transceiver.remoteCapabilities
          )

          var hasRtx = commonCapabilities.codecs.filter(function (c) {
            return c.name.toLowerCase() === 'rtx'
          }).length
          if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
            delete transceiver.sendEncodingParameters[0].rtx
          }

          pc._transceive(
            transceiver,
            direction === 'sendrecv' || direction === 'recvonly',
            direction === 'sendrecv' || direction === 'sendonly'
          )

          // TODO: rewrite to use http://w3c.github.io/webrtc-pc/#set-associated-remote-streams
          if (rtpReceiver && (direction === 'sendrecv' || direction === 'sendonly')) {
            track = rtpReceiver.track
            if (remoteMsid) {
              if (!streams[remoteMsid.stream]) {
                streams[remoteMsid.stream] = new window.MediaStream()
              }
              addTrackToStreamAndFireEvent(track, streams[remoteMsid.stream])
              receiverList.push([track, rtpReceiver, streams[remoteMsid.stream]])
            } else {
              if (!streams.default) {
                streams.default = new window.MediaStream()
              }
              addTrackToStreamAndFireEvent(track, streams.default)
              receiverList.push([track, rtpReceiver, streams.default])
            }
          } else {
            // FIXME: actually the receiver should be created later.
            delete transceiver.rtpReceiver
          }
        }
      })

      if (pc._dtlsRole === undefined) {
        pc._dtlsRole = description.type === 'offer' ? 'active' : 'passive'
      }

      pc._remoteDescription = {
        type: description.type,
        sdp: description.sdp,
      }
      if (description.type === 'offer') {
        pc._updateSignalingState('have-remote-offer')
      } else {
        pc._updateSignalingState('stable')
      }
      Object.keys(streams).forEach(function (sid) {
        var stream = streams[sid]
        if (stream.getTracks().length) {
          if (pc.remoteStreams.indexOf(stream) === -1) {
            pc.remoteStreams.push(stream)
            var event = new Event('addstream')
            event.stream = stream
            window.setTimeout(function () {
              pc._dispatchEvent('addstream', event)
            })
          }

          receiverList.forEach(function (item) {
            var track = item[0]
            var receiver = item[1]
            if (stream.id !== item[2].id) {
              return
            }
            fireAddTrack(pc, track, receiver, [stream])
          })
        }
      })
      receiverList.forEach(function (item) {
        if (item[2]) {
          return
        }
        fireAddTrack(pc, item[0], item[1], [])
      })

      // check whether addIceCandidate({}) was called within four seconds after
      // setRemoteDescription.
      window.setTimeout(function () {
        if (!(pc && pc.transceivers)) {
          return
        }
        pc.transceivers.forEach(function (transceiver) {
          if (
            transceiver.iceTransport &&
            transceiver.iceTransport.state === 'new' &&
            transceiver.iceTransport.getRemoteCandidates().length > 0
          ) {
            console.warn(
              'Timeout for addRemoteCandidate. Consider sending ' +
                'an end-of-candidates notification'
            )
            transceiver.iceTransport.addRemoteCandidate({})
          }
        })
      }, 4000)

      return Promise.resolve()
    }

    RTCPeerConnection.prototype.close = function () {
      this.transceivers.forEach(function (transceiver) {
        /* not yet
	      if (transceiver.iceGatherer) {
	        transceiver.iceGatherer.close();
	      }
	      */
        if (transceiver.iceTransport) {
          transceiver.iceTransport.stop()
        }
        if (transceiver.dtlsTransport) {
          transceiver.dtlsTransport.stop()
        }
        if (transceiver.rtpSender) {
          transceiver.rtpSender.stop()
        }
        if (transceiver.rtpReceiver) {
          transceiver.rtpReceiver.stop()
        }
      })
      // FIXME: clean up tracks, local streams, remote streams, etc
      this._isClosed = true
      this._updateSignalingState('closed')
    }

    // Update the signaling state.
    RTCPeerConnection.prototype._updateSignalingState = function (newState) {
      this.signalingState = newState
      var event = new Event('signalingstatechange')
      this._dispatchEvent('signalingstatechange', event)
    }

    // Determine whether to fire the negotiationneeded event.
    RTCPeerConnection.prototype._maybeFireNegotiationNeeded = function () {
      var pc = this
      if (this.signalingState !== 'stable' || this.needNegotiation === true) {
        return
      }
      this.needNegotiation = true
      window.setTimeout(function () {
        if (pc.needNegotiation) {
          pc.needNegotiation = false
          var event = new Event('negotiationneeded')
          pc._dispatchEvent('negotiationneeded', event)
        }
      }, 0)
    }

    // Update the ice connection state.
    RTCPeerConnection.prototype._updateIceConnectionState = function () {
      var newState
      var states = {
        new: 0,
        closed: 0,
        checking: 0,
        connected: 0,
        completed: 0,
        disconnected: 0,
        failed: 0,
      }
      this.transceivers.forEach(function (transceiver) {
        if (transceiver.iceTransport && !transceiver.rejected) {
          states[transceiver.iceTransport.state]++
        }
      })

      newState = 'new'
      if (states.failed > 0) {
        newState = 'failed'
      } else if (states.checking > 0) {
        newState = 'checking'
      } else if (states.disconnected > 0) {
        newState = 'disconnected'
      } else if (states.new > 0) {
        newState = 'new'
      } else if (states.connected > 0) {
        newState = 'connected'
      } else if (states.completed > 0) {
        newState = 'completed'
      }

      if (newState !== this.iceConnectionState) {
        this.iceConnectionState = newState
        var event = new Event('iceconnectionstatechange')
        this._dispatchEvent('iceconnectionstatechange', event)
      }
    }

    // Update the connection state.
    RTCPeerConnection.prototype._updateConnectionState = function () {
      var newState
      var states = {
        new: 0,
        closed: 0,
        connecting: 0,
        connected: 0,
        completed: 0,
        disconnected: 0,
        failed: 0,
      }
      this.transceivers.forEach(function (transceiver) {
        if (transceiver.iceTransport && transceiver.dtlsTransport && !transceiver.rejected) {
          states[transceiver.iceTransport.state]++
          states[transceiver.dtlsTransport.state]++
        }
      })
      // ICETransport.completed and connected are the same for this purpose.
      states.connected += states.completed

      newState = 'new'
      if (states.failed > 0) {
        newState = 'failed'
      } else if (states.connecting > 0) {
        newState = 'connecting'
      } else if (states.disconnected > 0) {
        newState = 'disconnected'
      } else if (states.new > 0) {
        newState = 'new'
      } else if (states.connected > 0) {
        newState = 'connected'
      }

      if (newState !== this.connectionState) {
        this.connectionState = newState
        var event = new Event('connectionstatechange')
        this._dispatchEvent('connectionstatechange', event)
      }
    }

    RTCPeerConnection.prototype.createOffer = function () {
      var pc = this

      if (pc._isClosed) {
        return Promise.reject(
          makeError('InvalidStateError', 'Can not call createOffer after close')
        )
      }

      var numAudioTracks = pc.transceivers.filter(function (t) {
        return t.kind === 'audio'
      }).length
      var numVideoTracks = pc.transceivers.filter(function (t) {
        return t.kind === 'video'
      }).length

      // Determine number of audio and video tracks we need to send/recv.
      var offerOptions = arguments[0]
      if (offerOptions) {
        // Reject Chrome legacy constraints.
        if (offerOptions.mandatory || offerOptions.optional) {
          throw new TypeError('Legacy mandatory/optional constraints not supported.')
        }
        if (offerOptions.offerToReceiveAudio !== undefined) {
          if (offerOptions.offerToReceiveAudio === true) {
            numAudioTracks = 1
          } else if (offerOptions.offerToReceiveAudio === false) {
            numAudioTracks = 0
          } else {
            numAudioTracks = offerOptions.offerToReceiveAudio
          }
        }
        if (offerOptions.offerToReceiveVideo !== undefined) {
          if (offerOptions.offerToReceiveVideo === true) {
            numVideoTracks = 1
          } else if (offerOptions.offerToReceiveVideo === false) {
            numVideoTracks = 0
          } else {
            numVideoTracks = offerOptions.offerToReceiveVideo
          }
        }
      }

      pc.transceivers.forEach(function (transceiver) {
        if (transceiver.kind === 'audio') {
          numAudioTracks--
          if (numAudioTracks < 0) {
            transceiver.wantReceive = false
          }
        } else if (transceiver.kind === 'video') {
          numVideoTracks--
          if (numVideoTracks < 0) {
            transceiver.wantReceive = false
          }
        }
      })

      // Create M-lines for recvonly streams.
      while (numAudioTracks > 0 || numVideoTracks > 0) {
        if (numAudioTracks > 0) {
          pc._createTransceiver('audio')
          numAudioTracks--
        }
        if (numVideoTracks > 0) {
          pc._createTransceiver('video')
          numVideoTracks--
        }
      }

      var sdp$1 = sdp.writeSessionBoilerplate(pc._sdpSessionId, pc._sdpSessionVersion++)
      pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
        // For each track, create an ice gatherer, ice transport,
        // dtls transport, potentially rtpsender and rtpreceiver.
        var track = transceiver.track
        var kind = transceiver.kind
        var mid = transceiver.mid || sdp.generateIdentifier()
        transceiver.mid = mid

        if (!transceiver.iceGatherer) {
          transceiver.iceGatherer = pc._createIceGatherer(sdpMLineIndex, pc.usingBundle)
        }

        var localCapabilities = window.RTCRtpSender.getCapabilities(kind)
        // filter RTX until additional stuff needed for RTX is implemented
        // in adapter.js
        if (edgeVersion < 15019) {
          localCapabilities.codecs = localCapabilities.codecs.filter(function (codec) {
            return codec.name !== 'rtx'
          })
        }
        localCapabilities.codecs.forEach(function (codec) {
          // work around https://bugs.chromium.org/p/webrtc/issues/detail?id=6552
          // by adding level-asymmetry-allowed=1
          if (codec.name === 'H264' && codec.parameters['level-asymmetry-allowed'] === undefined) {
            codec.parameters['level-asymmetry-allowed'] = '1'
          }

          // for subsequent offers, we might have to re-use the payload
          // type of the last offer.
          if (transceiver.remoteCapabilities && transceiver.remoteCapabilities.codecs) {
            transceiver.remoteCapabilities.codecs.forEach(function (remoteCodec) {
              if (
                codec.name.toLowerCase() === remoteCodec.name.toLowerCase() &&
                codec.clockRate === remoteCodec.clockRate
              ) {
                codec.preferredPayloadType = remoteCodec.payloadType
              }
            })
          }
        })
        localCapabilities.headerExtensions.forEach(function (hdrExt) {
          var remoteExtensions =
            (transceiver.remoteCapabilities && transceiver.remoteCapabilities.headerExtensions) ||
            []
          remoteExtensions.forEach(function (rHdrExt) {
            if (hdrExt.uri === rHdrExt.uri) {
              hdrExt.id = rHdrExt.id
            }
          })
        })

        // generate an ssrc now, to be used later in rtpSender.send
        var sendEncodingParameters = transceiver.sendEncodingParameters || [
          {
            ssrc: (2 * sdpMLineIndex + 1) * 1001,
          },
        ]
        if (track) {
          // add RTX
          if (edgeVersion >= 15019 && kind === 'video' && !sendEncodingParameters[0].rtx) {
            sendEncodingParameters[0].rtx = {
              ssrc: sendEncodingParameters[0].ssrc + 1,
            }
          }
        }

        if (transceiver.wantReceive) {
          transceiver.rtpReceiver = new window.RTCRtpReceiver(transceiver.dtlsTransport, kind)
        }

        transceiver.localCapabilities = localCapabilities
        transceiver.sendEncodingParameters = sendEncodingParameters
      })

      // always offer BUNDLE and dispose on return if not supported.
      if (pc._config.bundlePolicy !== 'max-compat') {
        sdp$1 +=
          'a=group:BUNDLE ' +
          pc.transceivers
            .map(function (t) {
              return t.mid
            })
            .join(' ') +
          '\r\n'
      }
      sdp$1 += 'a=ice-options:trickle\r\n'

      pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
        sdp$1 += writeMediaSection(
          transceiver,
          transceiver.localCapabilities,
          'offer',
          transceiver.stream,
          pc._dtlsRole
        )
        sdp$1 += 'a=rtcp-rsize\r\n'

        if (
          transceiver.iceGatherer &&
          pc.iceGatheringState !== 'new' &&
          (sdpMLineIndex === 0 || !pc.usingBundle)
        ) {
          transceiver.iceGatherer.getLocalCandidates().forEach(function (cand) {
            cand.component = 1
            sdp$1 += 'a=' + sdp.writeCandidate(cand) + '\r\n'
          })

          if (transceiver.iceGatherer.state === 'completed') {
            sdp$1 += 'a=end-of-candidates\r\n'
          }
        }
      })

      var desc = new window.RTCSessionDescription({
        type: 'offer',
        sdp: sdp$1,
      })
      return Promise.resolve(desc)
    }

    RTCPeerConnection.prototype.createAnswer = function () {
      var pc = this

      if (pc._isClosed) {
        return Promise.reject(
          makeError('InvalidStateError', 'Can not call createAnswer after close')
        )
      }

      if (
        !(pc.signalingState === 'have-remote-offer' || pc.signalingState === 'have-local-pranswer')
      ) {
        return Promise.reject(
          makeError(
            'InvalidStateError',
            'Can not call createAnswer in signalingState ' + pc.signalingState
          )
        )
      }

      var sdp$1 = sdp.writeSessionBoilerplate(pc._sdpSessionId, pc._sdpSessionVersion++)
      if (pc.usingBundle) {
        sdp$1 +=
          'a=group:BUNDLE ' +
          pc.transceivers
            .map(function (t) {
              return t.mid
            })
            .join(' ') +
          '\r\n'
      }
      sdp$1 += 'a=ice-options:trickle\r\n'

      var mediaSectionsInOffer = sdp.getMediaSections(pc._remoteDescription.sdp).length
      pc.transceivers.forEach(function (transceiver, sdpMLineIndex) {
        if (sdpMLineIndex + 1 > mediaSectionsInOffer) {
          return
        }
        if (transceiver.rejected) {
          if (transceiver.kind === 'application') {
            if (transceiver.protocol === 'DTLS/SCTP') {
              // legacy fmt
              sdp$1 += 'm=application 0 DTLS/SCTP 5000\r\n'
            } else {
              sdp$1 += 'm=application 0 ' + transceiver.protocol + ' webrtc-datachannel\r\n'
            }
          } else if (transceiver.kind === 'audio') {
            sdp$1 += 'm=audio 0 UDP/TLS/RTP/SAVPF 0\r\n' + 'a=rtpmap:0 PCMU/8000\r\n'
          } else if (transceiver.kind === 'video') {
            sdp$1 += 'm=video 0 UDP/TLS/RTP/SAVPF 120\r\n' + 'a=rtpmap:120 VP8/90000\r\n'
          }
          sdp$1 += 'c=IN IP4 0.0.0.0\r\n' + 'a=inactive\r\n' + 'a=mid:' + transceiver.mid + '\r\n'
          return
        }

        // FIXME: look at direction.
        if (transceiver.stream) {
          var localTrack
          if (transceiver.kind === 'audio') {
            localTrack = transceiver.stream.getAudioTracks()[0]
          } else if (transceiver.kind === 'video') {
            localTrack = transceiver.stream.getVideoTracks()[0]
          }
          if (localTrack) {
            // add RTX
            if (
              edgeVersion >= 15019 &&
              transceiver.kind === 'video' &&
              !transceiver.sendEncodingParameters[0].rtx
            ) {
              transceiver.sendEncodingParameters[0].rtx = {
                ssrc: transceiver.sendEncodingParameters[0].ssrc + 1,
              }
            }
          }
        }

        // Calculate intersection of capabilities.
        var commonCapabilities = getCommonCapabilities(
          transceiver.localCapabilities,
          transceiver.remoteCapabilities
        )

        var hasRtx = commonCapabilities.codecs.filter(function (c) {
          return c.name.toLowerCase() === 'rtx'
        }).length
        if (!hasRtx && transceiver.sendEncodingParameters[0].rtx) {
          delete transceiver.sendEncodingParameters[0].rtx
        }

        sdp$1 += writeMediaSection(
          transceiver,
          commonCapabilities,
          'answer',
          transceiver.stream,
          pc._dtlsRole
        )
        if (transceiver.rtcpParameters && transceiver.rtcpParameters.reducedSize) {
          sdp$1 += 'a=rtcp-rsize\r\n'
        }
      })

      var desc = new window.RTCSessionDescription({
        type: 'answer',
        sdp: sdp$1,
      })
      return Promise.resolve(desc)
    }

    RTCPeerConnection.prototype.addIceCandidate = function (candidate) {
      var pc = this
      var sections
      if (candidate && !(candidate.sdpMLineIndex !== undefined || candidate.sdpMid)) {
        return Promise.reject(new TypeError('sdpMLineIndex or sdpMid required'))
      }

      // TODO: needs to go into ops queue.
      return new Promise(function (resolve, reject) {
        if (!pc._remoteDescription) {
          return reject(
            makeError('InvalidStateError', 'Can not add ICE candidate without a remote description')
          )
        } else if (!candidate || candidate.candidate === '') {
          for (var j = 0; j < pc.transceivers.length; j++) {
            if (pc.transceivers[j].rejected) {
              continue
            }
            pc.transceivers[j].iceTransport.addRemoteCandidate({})
            sections = sdp.getMediaSections(pc._remoteDescription.sdp)
            sections[j] += 'a=end-of-candidates\r\n'
            pc._remoteDescription.sdp =
              sdp.getDescription(pc._remoteDescription.sdp) + sections.join('')
            if (pc.usingBundle) {
              break
            }
          }
        } else {
          var sdpMLineIndex = candidate.sdpMLineIndex
          if (candidate.sdpMid) {
            for (var i = 0; i < pc.transceivers.length; i++) {
              if (pc.transceivers[i].mid === candidate.sdpMid) {
                sdpMLineIndex = i
                break
              }
            }
          }
          var transceiver = pc.transceivers[sdpMLineIndex]
          if (transceiver) {
            if (transceiver.rejected) {
              return resolve()
            }
            var cand =
              Object.keys(candidate.candidate).length > 0
                ? sdp.parseCandidate(candidate.candidate)
                : {}
            // Ignore Chrome's invalid candidates since Edge does not like them.
            if (cand.protocol === 'tcp' && (cand.port === 0 || cand.port === 9)) {
              return resolve()
            }
            // Ignore RTCP candidates, we assume RTCP-MUX.
            if (cand.component && cand.component !== 1) {
              return resolve()
            }
            // when using bundle, avoid adding candidates to the wrong
            // ice transport. And avoid adding candidates added in the SDP.
            if (
              sdpMLineIndex === 0 ||
              (sdpMLineIndex > 0 && transceiver.iceTransport !== pc.transceivers[0].iceTransport)
            ) {
              if (!maybeAddCandidate(transceiver.iceTransport, cand)) {
                return reject(makeError('OperationError', 'Can not add ICE candidate'))
              }
            }

            // update the remoteDescription.
            var candidateString = candidate.candidate.trim()
            if (candidateString.indexOf('a=') === 0) {
              candidateString = candidateString.substr(2)
            }
            sections = sdp.getMediaSections(pc._remoteDescription.sdp)
            sections[sdpMLineIndex] +=
              'a=' + (cand.type ? candidateString : 'end-of-candidates') + '\r\n'
            pc._remoteDescription.sdp =
              sdp.getDescription(pc._remoteDescription.sdp) + sections.join('')
          } else {
            return reject(makeError('OperationError', 'Can not add ICE candidate'))
          }
        }
        resolve()
      })
    }

    RTCPeerConnection.prototype.getStats = function (selector) {
      if (selector && selector instanceof window.MediaStreamTrack) {
        var senderOrReceiver = null
        this.transceivers.forEach(function (transceiver) {
          if (transceiver.rtpSender && transceiver.rtpSender.track === selector) {
            senderOrReceiver = transceiver.rtpSender
          } else if (transceiver.rtpReceiver && transceiver.rtpReceiver.track === selector) {
            senderOrReceiver = transceiver.rtpReceiver
          }
        })
        if (!senderOrReceiver) {
          throw makeError('InvalidAccessError', 'Invalid selector.')
        }
        return senderOrReceiver.getStats()
      }

      var promises = []
      this.transceivers.forEach(function (transceiver) {
        ;['rtpSender', 'rtpReceiver', 'iceGatherer', 'iceTransport', 'dtlsTransport'].forEach(
          function (method) {
            if (transceiver[method]) {
              promises.push(transceiver[method].getStats())
            }
          }
        )
      })
      return Promise.all(promises).then(function (allStats) {
        var results = new Map()
        allStats.forEach(function (stats) {
          stats.forEach(function (stat) {
            results.set(stat.id, stat)
          })
        })
        return results
      })
    }

    // fix low-level stat names and return Map instead of object.
    var ortcObjects = [
      'RTCRtpSender',
      'RTCRtpReceiver',
      'RTCIceGatherer',
      'RTCIceTransport',
      'RTCDtlsTransport',
    ]
    ortcObjects.forEach(function (ortcObjectName) {
      var obj = window[ortcObjectName]
      if (obj && obj.prototype && obj.prototype.getStats) {
        var nativeGetstats = obj.prototype.getStats
        obj.prototype.getStats = function () {
          return nativeGetstats.apply(this).then(function (nativeStats) {
            var mapStats = new Map()
            Object.keys(nativeStats).forEach(function (id) {
              nativeStats[id].type = fixStatsType(nativeStats[id])
              mapStats.set(id, nativeStats[id])
            })
            return mapStats
          })
        }
      }
    })

    // legacy callback shims. Should be moved to adapter.js some days.
    var methods = ['createOffer', 'createAnswer']
    methods.forEach(function (method) {
      var nativeMethod = RTCPeerConnection.prototype[method]
      RTCPeerConnection.prototype[method] = function () {
        var args = arguments
        if (typeof args[0] === 'function' || typeof args[1] === 'function') {
          // legacy
          return nativeMethod.apply(this, [arguments[2]]).then(
            function (description) {
              if (typeof args[0] === 'function') {
                args[0].apply(null, [description])
              }
            },
            function (error) {
              if (typeof args[1] === 'function') {
                args[1].apply(null, [error])
              }
            }
          )
        }
        return nativeMethod.apply(this, arguments)
      }
    })

    methods = ['setLocalDescription', 'setRemoteDescription', 'addIceCandidate']
    methods.forEach(function (method) {
      var nativeMethod = RTCPeerConnection.prototype[method]
      RTCPeerConnection.prototype[method] = function () {
        var args = arguments
        if (typeof args[1] === 'function' || typeof args[2] === 'function') {
          // legacy
          return nativeMethod.apply(this, arguments).then(
            function () {
              if (typeof args[1] === 'function') {
                args[1].apply(null)
              }
            },
            function (error) {
              if (typeof args[2] === 'function') {
                args[2].apply(null, [error])
              }
            }
          )
        }
        return nativeMethod.apply(this, arguments)
      }
    })

    // getStats is special. It doesn't have a spec legacy method yet we support
    // getStats(something, cb) without error callbacks.
    ;['getStats'].forEach(function (method) {
      var nativeMethod = RTCPeerConnection.prototype[method]
      RTCPeerConnection.prototype[method] = function () {
        var args = arguments
        if (typeof args[1] === 'function') {
          return nativeMethod.apply(this, arguments).then(function () {
            if (typeof args[1] === 'function') {
              args[1].apply(null)
            }
          })
        }
        return nativeMethod.apply(this, arguments)
      }
    })

    return RTCPeerConnection
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimGetUserMedia$2(window) {
    const navigator = window && window.navigator

    const shimError_ = function (e) {
      return {
        name: { PermissionDeniedError: 'NotAllowedError' }[e.name] || e.name,
        message: e.message,
        constraint: e.constraint,
        toString() {
          return this.name
        },
      }
    }

    // getUserMedia error shim.
    const origGetUserMedia = navigator.mediaDevices.getUserMedia.bind(navigator.mediaDevices)
    navigator.mediaDevices.getUserMedia = function (c) {
      return origGetUserMedia(c).catch((e) => Promise.reject(shimError_(e)))
    }
  }

  /*
   *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimGetDisplayMedia$1(window) {
    if (!('getDisplayMedia' in window.navigator)) {
      return
    }
    if (!window.navigator.mediaDevices) {
      return
    }
    if (window.navigator.mediaDevices && 'getDisplayMedia' in window.navigator.mediaDevices) {
      return
    }
    window.navigator.mediaDevices.getDisplayMedia = window.navigator.getDisplayMedia.bind(
      window.navigator
    )
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimPeerConnection$1(window, browserDetails) {
    if (window.RTCIceGatherer) {
      if (!window.RTCIceCandidate) {
        window.RTCIceCandidate = function RTCIceCandidate(args) {
          return args
        }
      }
      if (!window.RTCSessionDescription) {
        window.RTCSessionDescription = function RTCSessionDescription(args) {
          return args
        }
      }
      // this adds an additional event listener to MediaStrackTrack that signals
      // when a tracks enabled property was changed. Workaround for a bug in
      // addStream, see below. No longer required in 15025+
      if (browserDetails.version < 15025) {
        const origMSTEnabled = Object.getOwnPropertyDescriptor(
          window.MediaStreamTrack.prototype,
          'enabled'
        )
        Object.defineProperty(window.MediaStreamTrack.prototype, 'enabled', {
          set(value) {
            origMSTEnabled.set.call(this, value)
            const ev = new Event('enabled')
            ev.enabled = value
            this.dispatchEvent(ev)
          },
        })
      }
    }

    // ORTC defines the DTMF sender a bit different.
    // https://github.com/w3c/ortc/issues/714
    if (window.RTCRtpSender && !('dtmf' in window.RTCRtpSender.prototype)) {
      Object.defineProperty(window.RTCRtpSender.prototype, 'dtmf', {
        get() {
          if (this._dtmf === undefined) {
            if (this.track.kind === 'audio') {
              this._dtmf = new window.RTCDtmfSender(this)
            } else if (this.track.kind === 'video') {
              this._dtmf = null
            }
          }
          return this._dtmf
        },
      })
    }
    // Edge currently only implements the RTCDtmfSender, not the
    // RTCDTMFSender alias. See http://draft.ortc.org/#rtcdtmfsender2*
    if (window.RTCDtmfSender && !window.RTCDTMFSender) {
      window.RTCDTMFSender = window.RTCDtmfSender
    }

    const RTCPeerConnectionShim = rtcpeerconnection(window, browserDetails.version)
    window.RTCPeerConnection = function RTCPeerConnection(config) {
      if (config && config.iceServers) {
        config.iceServers = filterIceServers$1(config.iceServers, browserDetails.version)
        log$1('ICE servers after filtering:', config.iceServers)
      }
      return new RTCPeerConnectionShim(config)
    }
    window.RTCPeerConnection.prototype = RTCPeerConnectionShim.prototype
  }

  function shimReplaceTrack(window) {
    // ORTC has replaceTrack -- https://github.com/w3c/ortc/issues/614
    if (window.RTCRtpSender && !('replaceTrack' in window.RTCRtpSender.prototype)) {
      window.RTCRtpSender.prototype.replaceTrack = window.RTCRtpSender.prototype.setTrack
    }
  }

  var edgeShim = /*#__PURE__*/ Object.freeze({
    __proto__: null,
    shimPeerConnection: shimPeerConnection$1,
    shimReplaceTrack: shimReplaceTrack,
    shimGetUserMedia: shimGetUserMedia$2,
    shimGetDisplayMedia: shimGetDisplayMedia$1,
  })

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimGetUserMedia$1(window, browserDetails) {
    const navigator = window && window.navigator
    const MediaStreamTrack = window && window.MediaStreamTrack

    navigator.getUserMedia = function (constraints, onSuccess, onError) {
      // Replace Firefox 44+'s deprecation warning with unprefixed version.
      deprecated('navigator.getUserMedia', 'navigator.mediaDevices.getUserMedia')
      navigator.mediaDevices.getUserMedia(constraints).then(onSuccess, onError)
    }

    if (
      !(
        browserDetails.version > 55 &&
        'autoGainControl' in navigator.mediaDevices.getSupportedConstraints()
      )
    ) {
      const remap = function (obj, a, b) {
        if (a in obj && !(b in obj)) {
          obj[b] = obj[a]
          delete obj[a]
        }
      }

      const nativeGetUserMedia = navigator.mediaDevices.getUserMedia.bind(navigator.mediaDevices)
      navigator.mediaDevices.getUserMedia = function (c) {
        if (typeof c === 'object' && typeof c.audio === 'object') {
          c = JSON.parse(JSON.stringify(c))
          remap(c.audio, 'autoGainControl', 'mozAutoGainControl')
          remap(c.audio, 'noiseSuppression', 'mozNoiseSuppression')
        }
        return nativeGetUserMedia(c)
      }

      if (MediaStreamTrack && MediaStreamTrack.prototype.getSettings) {
        const nativeGetSettings = MediaStreamTrack.prototype.getSettings
        MediaStreamTrack.prototype.getSettings = function () {
          const obj = nativeGetSettings.apply(this, arguments)
          remap(obj, 'mozAutoGainControl', 'autoGainControl')
          remap(obj, 'mozNoiseSuppression', 'noiseSuppression')
          return obj
        }
      }

      if (MediaStreamTrack && MediaStreamTrack.prototype.applyConstraints) {
        const nativeApplyConstraints = MediaStreamTrack.prototype.applyConstraints
        MediaStreamTrack.prototype.applyConstraints = function (c) {
          if (this.kind === 'audio' && typeof c === 'object') {
            c = JSON.parse(JSON.stringify(c))
            remap(c, 'autoGainControl', 'mozAutoGainControl')
            remap(c, 'noiseSuppression', 'mozNoiseSuppression')
          }
          return nativeApplyConstraints.apply(this, [c])
        }
      }
    }
  }

  /*
   *  Copyright (c) 2018 The adapter.js project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimGetDisplayMedia(window, preferredMediaSource) {
    if (window.navigator.mediaDevices && 'getDisplayMedia' in window.navigator.mediaDevices) {
      return
    }
    if (!window.navigator.mediaDevices) {
      return
    }
    window.navigator.mediaDevices.getDisplayMedia = function getDisplayMedia(constraints) {
      if (!(constraints && constraints.video)) {
        const err = new DOMException('getDisplayMedia without video ' + 'constraints is undefined')
        err.name = 'NotFoundError'
        // from https://heycam.github.io/webidl/#idl-DOMException-error-names
        err.code = 8
        return Promise.reject(err)
      }
      if (constraints.video === true) {
        constraints.video = { mediaSource: preferredMediaSource }
      } else {
        constraints.video.mediaSource = preferredMediaSource
      }
      return window.navigator.mediaDevices.getUserMedia(constraints)
    }
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimOnTrack(window) {
    if (
      typeof window === 'object' &&
      window.RTCTrackEvent &&
      'receiver' in window.RTCTrackEvent.prototype &&
      !('transceiver' in window.RTCTrackEvent.prototype)
    ) {
      Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
        get() {
          return { receiver: this.receiver }
        },
      })
    }
  }

  function shimPeerConnection(window, browserDetails) {
    if (typeof window !== 'object' || !(window.RTCPeerConnection || window.mozRTCPeerConnection)) {
      return // probably media.peerconnection.enabled=false in about:config
    }
    if (!window.RTCPeerConnection && window.mozRTCPeerConnection) {
      // very basic support for old versions.
      window.RTCPeerConnection = window.mozRTCPeerConnection
    }

    if (browserDetails.version < 53) {
      // shim away need for obsolete RTCIceCandidate/RTCSessionDescription.
      ;['setLocalDescription', 'setRemoteDescription', 'addIceCandidate'].forEach(function (
        method
      ) {
        const nativeMethod = window.RTCPeerConnection.prototype[method]
        const methodObj = {
          [method]() {
            arguments[0] = new (
              method === 'addIceCandidate' ? window.RTCIceCandidate : window.RTCSessionDescription
            )(arguments[0])
            return nativeMethod.apply(this, arguments)
          },
        }
        window.RTCPeerConnection.prototype[method] = methodObj[method]
      })
    }

    const modernStatsTypes = {
      inboundrtp: 'inbound-rtp',
      outboundrtp: 'outbound-rtp',
      candidatepair: 'candidate-pair',
      localcandidate: 'local-candidate',
      remotecandidate: 'remote-candidate',
    }

    const nativeGetStats = window.RTCPeerConnection.prototype.getStats
    window.RTCPeerConnection.prototype.getStats = function getStats() {
      const [selector, onSucc, onErr] = arguments
      return nativeGetStats
        .apply(this, [selector || null])
        .then((stats) => {
          if (browserDetails.version < 53 && !onSucc) {
            // Shim only promise getStats with spec-hyphens in type names
            // Leave callback version alone; misc old uses of forEach before Map
            try {
              stats.forEach((stat) => {
                stat.type = modernStatsTypes[stat.type] || stat.type
              })
            } catch (e) {
              if (e.name !== 'TypeError') {
                throw e
              }
              // Avoid TypeError: "type" is read-only, in old versions. 34-43ish
              stats.forEach((stat, i) => {
                stats.set(
                  i,
                  Object.assign({}, stat, {
                    type: modernStatsTypes[stat.type] || stat.type,
                  })
                )
              })
            }
          }
          return stats
        })
        .then(onSucc, onErr)
    }
  }

  function shimSenderGetStats(window) {
    if (!(typeof window === 'object' && window.RTCPeerConnection && window.RTCRtpSender)) {
      return
    }
    if (window.RTCRtpSender && 'getStats' in window.RTCRtpSender.prototype) {
      return
    }
    const origGetSenders = window.RTCPeerConnection.prototype.getSenders
    if (origGetSenders) {
      window.RTCPeerConnection.prototype.getSenders = function getSenders() {
        const senders = origGetSenders.apply(this, [])
        senders.forEach((sender) => (sender._pc = this))
        return senders
      }
    }

    const origAddTrack = window.RTCPeerConnection.prototype.addTrack
    if (origAddTrack) {
      window.RTCPeerConnection.prototype.addTrack = function addTrack() {
        const sender = origAddTrack.apply(this, arguments)
        sender._pc = this
        return sender
      }
    }
    window.RTCRtpSender.prototype.getStats = function getStats() {
      return this.track ? this._pc.getStats(this.track) : Promise.resolve(new Map())
    }
  }

  function shimReceiverGetStats(window) {
    if (!(typeof window === 'object' && window.RTCPeerConnection && window.RTCRtpSender)) {
      return
    }
    if (window.RTCRtpSender && 'getStats' in window.RTCRtpReceiver.prototype) {
      return
    }
    const origGetReceivers = window.RTCPeerConnection.prototype.getReceivers
    if (origGetReceivers) {
      window.RTCPeerConnection.prototype.getReceivers = function getReceivers() {
        const receivers = origGetReceivers.apply(this, [])
        receivers.forEach((receiver) => (receiver._pc = this))
        return receivers
      }
    }
    wrapPeerConnectionEvent(window, 'track', (e) => {
      e.receiver._pc = e.srcElement
      return e
    })
    window.RTCRtpReceiver.prototype.getStats = function getStats() {
      return this._pc.getStats(this.track)
    }
  }

  function shimRemoveStream(window) {
    if (!window.RTCPeerConnection || 'removeStream' in window.RTCPeerConnection.prototype) {
      return
    }
    window.RTCPeerConnection.prototype.removeStream = function removeStream(stream) {
      deprecated('removeStream', 'removeTrack')
      this.getSenders().forEach((sender) => {
        if (sender.track && stream.getTracks().includes(sender.track)) {
          this.removeTrack(sender)
        }
      })
    }
  }

  function shimRTCDataChannel(window) {
    // rename DataChannel to RTCDataChannel (native fix in FF60):
    // https://bugzilla.mozilla.org/show_bug.cgi?id=1173851
    if (window.DataChannel && !window.RTCDataChannel) {
      window.RTCDataChannel = window.DataChannel
    }
  }

  function shimAddTransceiver(window) {
    // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
    // Firefox ignores the init sendEncodings options passed to addTransceiver
    // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
    if (!(typeof window === 'object' && window.RTCPeerConnection)) {
      return
    }
    const origAddTransceiver = window.RTCPeerConnection.prototype.addTransceiver
    if (origAddTransceiver) {
      window.RTCPeerConnection.prototype.addTransceiver = function addTransceiver() {
        this.setParametersPromises = []
        const initParameters = arguments[1]
        const shouldPerformCheck = initParameters && 'sendEncodings' in initParameters
        if (shouldPerformCheck) {
          // If sendEncodings params are provided, validate grammar
          initParameters.sendEncodings.forEach((encodingParam) => {
            if ('rid' in encodingParam) {
              const ridRegex = /^[a-z0-9]{0,16}$/i
              if (!ridRegex.test(encodingParam.rid)) {
                throw new TypeError('Invalid RID value provided.')
              }
            }
            if ('scaleResolutionDownBy' in encodingParam) {
              if (!(parseFloat(encodingParam.scaleResolutionDownBy) >= 1.0)) {
                throw new RangeError('scale_resolution_down_by must be >= 1.0')
              }
            }
            if ('maxFramerate' in encodingParam) {
              if (!(parseFloat(encodingParam.maxFramerate) >= 0)) {
                throw new RangeError('max_framerate must be >= 0.0')
              }
            }
          })
        }
        const transceiver = origAddTransceiver.apply(this, arguments)
        if (shouldPerformCheck) {
          // Check if the init options were applied. If not we do this in an
          // asynchronous way and save the promise reference in a global object.
          // This is an ugly hack, but at the same time is way more robust than
          // checking the sender parameters before and after the createOffer
          // Also note that after the createoffer we are not 100% sure that
          // the params were asynchronously applied so we might miss the
          // opportunity to recreate offer.
          const { sender } = transceiver
          const params = sender.getParameters()
          if (
            !('encodings' in params) ||
            // Avoid being fooled by patched getParameters() below.
            (params.encodings.length === 1 && Object.keys(params.encodings[0]).length === 0)
          ) {
            params.encodings = initParameters.sendEncodings
            sender.sendEncodings = initParameters.sendEncodings
            this.setParametersPromises.push(
              sender
                .setParameters(params)
                .then(() => {
                  delete sender.sendEncodings
                })
                .catch(() => {
                  delete sender.sendEncodings
                })
            )
          }
        }
        return transceiver
      }
    }
  }

  function shimGetParameters(window) {
    if (!(typeof window === 'object' && window.RTCRtpSender)) {
      return
    }
    const origGetParameters = window.RTCRtpSender.prototype.getParameters
    if (origGetParameters) {
      window.RTCRtpSender.prototype.getParameters = function getParameters() {
        const params = origGetParameters.apply(this, arguments)
        if (!('encodings' in params)) {
          params.encodings = [].concat(this.sendEncodings || [{}])
        }
        return params
      }
    }
  }

  function shimCreateOffer(window) {
    // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
    // Firefox ignores the init sendEncodings options passed to addTransceiver
    // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
    if (!(typeof window === 'object' && window.RTCPeerConnection)) {
      return
    }
    const origCreateOffer = window.RTCPeerConnection.prototype.createOffer
    window.RTCPeerConnection.prototype.createOffer = function createOffer() {
      if (this.setParametersPromises && this.setParametersPromises.length) {
        return Promise.all(this.setParametersPromises)
          .then(() => {
            return origCreateOffer.apply(this, arguments)
          })
          .finally(() => {
            this.setParametersPromises = []
          })
      }
      return origCreateOffer.apply(this, arguments)
    }
  }

  function shimCreateAnswer(window) {
    // https://github.com/webrtcHacks/adapter/issues/998#issuecomment-516921647
    // Firefox ignores the init sendEncodings options passed to addTransceiver
    // https://bugzilla.mozilla.org/show_bug.cgi?id=1396918
    if (!(typeof window === 'object' && window.RTCPeerConnection)) {
      return
    }
    const origCreateAnswer = window.RTCPeerConnection.prototype.createAnswer
    window.RTCPeerConnection.prototype.createAnswer = function createAnswer() {
      if (this.setParametersPromises && this.setParametersPromises.length) {
        return Promise.all(this.setParametersPromises)
          .then(() => {
            return origCreateAnswer.apply(this, arguments)
          })
          .finally(() => {
            this.setParametersPromises = []
          })
      }
      return origCreateAnswer.apply(this, arguments)
    }
  }

  var firefoxShim = /*#__PURE__*/ Object.freeze({
    __proto__: null,
    shimOnTrack: shimOnTrack,
    shimPeerConnection: shimPeerConnection,
    shimSenderGetStats: shimSenderGetStats,
    shimReceiverGetStats: shimReceiverGetStats,
    shimRemoveStream: shimRemoveStream,
    shimRTCDataChannel: shimRTCDataChannel,
    shimAddTransceiver: shimAddTransceiver,
    shimGetParameters: shimGetParameters,
    shimCreateOffer: shimCreateOffer,
    shimCreateAnswer: shimCreateAnswer,
    shimGetUserMedia: shimGetUserMedia$1,
    shimGetDisplayMedia: shimGetDisplayMedia,
  })

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimLocalStreamsAPI(window) {
    if (typeof window !== 'object' || !window.RTCPeerConnection) {
      return
    }
    if (!('getLocalStreams' in window.RTCPeerConnection.prototype)) {
      window.RTCPeerConnection.prototype.getLocalStreams = function getLocalStreams() {
        if (!this._localStreams) {
          this._localStreams = []
        }
        return this._localStreams
      }
    }
    if (!('addStream' in window.RTCPeerConnection.prototype)) {
      const _addTrack = window.RTCPeerConnection.prototype.addTrack
      window.RTCPeerConnection.prototype.addStream = function addStream(stream) {
        if (!this._localStreams) {
          this._localStreams = []
        }
        if (!this._localStreams.includes(stream)) {
          this._localStreams.push(stream)
        }
        // Try to emulate Chrome's behaviour of adding in audio-video order.
        // Safari orders by track id.
        stream.getAudioTracks().forEach((track) => _addTrack.call(this, track, stream))
        stream.getVideoTracks().forEach((track) => _addTrack.call(this, track, stream))
      }

      window.RTCPeerConnection.prototype.addTrack = function addTrack(track, ...streams) {
        if (streams) {
          streams.forEach((stream) => {
            if (!this._localStreams) {
              this._localStreams = [stream]
            } else if (!this._localStreams.includes(stream)) {
              this._localStreams.push(stream)
            }
          })
        }
        return _addTrack.apply(this, arguments)
      }
    }
    if (!('removeStream' in window.RTCPeerConnection.prototype)) {
      window.RTCPeerConnection.prototype.removeStream = function removeStream(stream) {
        if (!this._localStreams) {
          this._localStreams = []
        }
        const index = this._localStreams.indexOf(stream)
        if (index === -1) {
          return
        }
        this._localStreams.splice(index, 1)
        const tracks = stream.getTracks()
        this.getSenders().forEach((sender) => {
          if (tracks.includes(sender.track)) {
            this.removeTrack(sender)
          }
        })
      }
    }
  }

  function shimRemoteStreamsAPI(window) {
    if (typeof window !== 'object' || !window.RTCPeerConnection) {
      return
    }
    if (!('getRemoteStreams' in window.RTCPeerConnection.prototype)) {
      window.RTCPeerConnection.prototype.getRemoteStreams = function getRemoteStreams() {
        return this._remoteStreams ? this._remoteStreams : []
      }
    }
    if (!('onaddstream' in window.RTCPeerConnection.prototype)) {
      Object.defineProperty(window.RTCPeerConnection.prototype, 'onaddstream', {
        get() {
          return this._onaddstream
        },
        set(f) {
          if (this._onaddstream) {
            this.removeEventListener('addstream', this._onaddstream)
            this.removeEventListener('track', this._onaddstreampoly)
          }
          this.addEventListener('addstream', (this._onaddstream = f))
          this.addEventListener(
            'track',
            (this._onaddstreampoly = (e) => {
              e.streams.forEach((stream) => {
                if (!this._remoteStreams) {
                  this._remoteStreams = []
                }
                if (this._remoteStreams.includes(stream)) {
                  return
                }
                this._remoteStreams.push(stream)
                const event = new Event('addstream')
                event.stream = stream
                this.dispatchEvent(event)
              })
            })
          )
        },
      })
      const origSetRemoteDescription = window.RTCPeerConnection.prototype.setRemoteDescription
      window.RTCPeerConnection.prototype.setRemoteDescription = function setRemoteDescription() {
        const pc = this
        if (!this._onaddstreampoly) {
          this.addEventListener(
            'track',
            (this._onaddstreampoly = function (e) {
              e.streams.forEach((stream) => {
                if (!pc._remoteStreams) {
                  pc._remoteStreams = []
                }
                if (pc._remoteStreams.indexOf(stream) >= 0) {
                  return
                }
                pc._remoteStreams.push(stream)
                const event = new Event('addstream')
                event.stream = stream
                pc.dispatchEvent(event)
              })
            })
          )
        }
        return origSetRemoteDescription.apply(pc, arguments)
      }
    }
  }

  function shimCallbacksAPI(window) {
    if (typeof window !== 'object' || !window.RTCPeerConnection) {
      return
    }
    const prototype = window.RTCPeerConnection.prototype
    const origCreateOffer = prototype.createOffer
    const origCreateAnswer = prototype.createAnswer
    const setLocalDescription = prototype.setLocalDescription
    const setRemoteDescription = prototype.setRemoteDescription
    const addIceCandidate = prototype.addIceCandidate

    prototype.createOffer = function createOffer(successCallback, failureCallback) {
      const options = arguments.length >= 2 ? arguments[2] : arguments[0]
      const promise = origCreateOffer.apply(this, [options])
      if (!failureCallback) {
        return promise
      }
      promise.then(successCallback, failureCallback)
      return Promise.resolve()
    }

    prototype.createAnswer = function createAnswer(successCallback, failureCallback) {
      const options = arguments.length >= 2 ? arguments[2] : arguments[0]
      const promise = origCreateAnswer.apply(this, [options])
      if (!failureCallback) {
        return promise
      }
      promise.then(successCallback, failureCallback)
      return Promise.resolve()
    }

    let withCallback = function (description, successCallback, failureCallback) {
      const promise = setLocalDescription.apply(this, [description])
      if (!failureCallback) {
        return promise
      }
      promise.then(successCallback, failureCallback)
      return Promise.resolve()
    }
    prototype.setLocalDescription = withCallback

    withCallback = function (description, successCallback, failureCallback) {
      const promise = setRemoteDescription.apply(this, [description])
      if (!failureCallback) {
        return promise
      }
      promise.then(successCallback, failureCallback)
      return Promise.resolve()
    }
    prototype.setRemoteDescription = withCallback

    withCallback = function (candidate, successCallback, failureCallback) {
      const promise = addIceCandidate.apply(this, [candidate])
      if (!failureCallback) {
        return promise
      }
      promise.then(successCallback, failureCallback)
      return Promise.resolve()
    }
    prototype.addIceCandidate = withCallback
  }

  function shimGetUserMedia(window) {
    const navigator = window && window.navigator

    if (navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
      // shim not needed in Safari 12.1
      const mediaDevices = navigator.mediaDevices
      const _getUserMedia = mediaDevices.getUserMedia.bind(mediaDevices)
      navigator.mediaDevices.getUserMedia = (constraints) => {
        return _getUserMedia(shimConstraints(constraints))
      }
    }

    if (!navigator.getUserMedia && navigator.mediaDevices && navigator.mediaDevices.getUserMedia) {
      navigator.getUserMedia = function getUserMedia(constraints, cb, errcb) {
        navigator.mediaDevices.getUserMedia(constraints).then(cb, errcb)
      }.bind(navigator)
    }
  }

  function shimConstraints(constraints) {
    if (constraints && constraints.video !== undefined) {
      return Object.assign({}, constraints, { video: compactObject(constraints.video) })
    }

    return constraints
  }

  function shimRTCIceServerUrls(window) {
    if (!window.RTCPeerConnection) {
      return
    }
    // migrate from non-spec RTCIceServer.url to RTCIceServer.urls
    const OrigPeerConnection = window.RTCPeerConnection
    window.RTCPeerConnection = function RTCPeerConnection(pcConfig, pcConstraints) {
      if (pcConfig && pcConfig.iceServers) {
        const newIceServers = []
        for (let i = 0; i < pcConfig.iceServers.length; i++) {
          let server = pcConfig.iceServers[i]
          if (!server.hasOwnProperty('urls') && server.hasOwnProperty('url')) {
            deprecated('RTCIceServer.url', 'RTCIceServer.urls')
            server = JSON.parse(JSON.stringify(server))
            server.urls = server.url
            delete server.url
            newIceServers.push(server)
          } else {
            newIceServers.push(pcConfig.iceServers[i])
          }
        }
        pcConfig.iceServers = newIceServers
      }
      return new OrigPeerConnection(pcConfig, pcConstraints)
    }
    window.RTCPeerConnection.prototype = OrigPeerConnection.prototype
    // wrap static methods. Currently just generateCertificate.
    if ('generateCertificate' in OrigPeerConnection) {
      Object.defineProperty(window.RTCPeerConnection, 'generateCertificate', {
        get() {
          return OrigPeerConnection.generateCertificate
        },
      })
    }
  }

  function shimTrackEventTransceiver(window) {
    // Add event.transceiver member over deprecated event.receiver
    if (
      typeof window === 'object' &&
      window.RTCTrackEvent &&
      'receiver' in window.RTCTrackEvent.prototype &&
      !('transceiver' in window.RTCTrackEvent.prototype)
    ) {
      Object.defineProperty(window.RTCTrackEvent.prototype, 'transceiver', {
        get() {
          return { receiver: this.receiver }
        },
      })
    }
  }

  function shimCreateOfferLegacy(window) {
    const origCreateOffer = window.RTCPeerConnection.prototype.createOffer
    window.RTCPeerConnection.prototype.createOffer = function createOffer(offerOptions) {
      if (offerOptions) {
        if (typeof offerOptions.offerToReceiveAudio !== 'undefined') {
          // support bit values
          offerOptions.offerToReceiveAudio = !!offerOptions.offerToReceiveAudio
        }
        const audioTransceiver = this.getTransceivers().find(
          (transceiver) => transceiver.receiver.track.kind === 'audio'
        )
        if (offerOptions.offerToReceiveAudio === false && audioTransceiver) {
          if (audioTransceiver.direction === 'sendrecv') {
            if (audioTransceiver.setDirection) {
              audioTransceiver.setDirection('sendonly')
            } else {
              audioTransceiver.direction = 'sendonly'
            }
          } else if (audioTransceiver.direction === 'recvonly') {
            if (audioTransceiver.setDirection) {
              audioTransceiver.setDirection('inactive')
            } else {
              audioTransceiver.direction = 'inactive'
            }
          }
        } else if (offerOptions.offerToReceiveAudio === true && !audioTransceiver) {
          this.addTransceiver('audio')
        }

        if (typeof offerOptions.offerToReceiveVideo !== 'undefined') {
          // support bit values
          offerOptions.offerToReceiveVideo = !!offerOptions.offerToReceiveVideo
        }
        const videoTransceiver = this.getTransceivers().find(
          (transceiver) => transceiver.receiver.track.kind === 'video'
        )
        if (offerOptions.offerToReceiveVideo === false && videoTransceiver) {
          if (videoTransceiver.direction === 'sendrecv') {
            if (videoTransceiver.setDirection) {
              videoTransceiver.setDirection('sendonly')
            } else {
              videoTransceiver.direction = 'sendonly'
            }
          } else if (videoTransceiver.direction === 'recvonly') {
            if (videoTransceiver.setDirection) {
              videoTransceiver.setDirection('inactive')
            } else {
              videoTransceiver.direction = 'inactive'
            }
          }
        } else if (offerOptions.offerToReceiveVideo === true && !videoTransceiver) {
          this.addTransceiver('video')
        }
      }
      return origCreateOffer.apply(this, arguments)
    }
  }

  function shimAudioContext(window) {
    if (typeof window !== 'object' || window.AudioContext) {
      return
    }
    window.AudioContext = window.webkitAudioContext
  }

  var safariShim = /*#__PURE__*/ Object.freeze({
    __proto__: null,
    shimLocalStreamsAPI: shimLocalStreamsAPI,
    shimRemoteStreamsAPI: shimRemoteStreamsAPI,
    shimCallbacksAPI: shimCallbacksAPI,
    shimGetUserMedia: shimGetUserMedia,
    shimConstraints: shimConstraints,
    shimRTCIceServerUrls: shimRTCIceServerUrls,
    shimTrackEventTransceiver: shimTrackEventTransceiver,
    shimCreateOfferLegacy: shimCreateOfferLegacy,
    shimAudioContext: shimAudioContext,
  })

  /*
   *  Copyright (c) 2017 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  function shimRTCIceCandidate(window) {
    // foundation is arbitrarily chosen as an indicator for full support for
    // https://w3c.github.io/webrtc-pc/#rtcicecandidate-interface
    if (
      !window.RTCIceCandidate ||
      (window.RTCIceCandidate && 'foundation' in window.RTCIceCandidate.prototype)
    ) {
      return
    }

    const NativeRTCIceCandidate = window.RTCIceCandidate
    window.RTCIceCandidate = function RTCIceCandidate(args) {
      // Remove the a= which shouldn't be part of the candidate string.
      if (typeof args === 'object' && args.candidate && args.candidate.indexOf('a=') === 0) {
        args = JSON.parse(JSON.stringify(args))
        args.candidate = args.candidate.substr(2)
      }

      if (args.candidate && args.candidate.length) {
        // Augment the native candidate with the parsed fields.
        const nativeCandidate = new NativeRTCIceCandidate(args)
        const parsedCandidate = sdp.parseCandidate(args.candidate)
        const augmentedCandidate = Object.assign(nativeCandidate, parsedCandidate)

        // Add a serializer that does not serialize the extra attributes.
        augmentedCandidate.toJSON = function toJSON() {
          return {
            candidate: augmentedCandidate.candidate,
            sdpMid: augmentedCandidate.sdpMid,
            sdpMLineIndex: augmentedCandidate.sdpMLineIndex,
            usernameFragment: augmentedCandidate.usernameFragment,
          }
        }
        return augmentedCandidate
      }
      return new NativeRTCIceCandidate(args)
    }
    window.RTCIceCandidate.prototype = NativeRTCIceCandidate.prototype

    // Hook up the augmented candidate in onicecandidate and
    // addEventListener('icecandidate', ...)
    wrapPeerConnectionEvent(window, 'icecandidate', (e) => {
      if (e.candidate) {
        Object.defineProperty(e, 'candidate', {
          value: new window.RTCIceCandidate(e.candidate),
          writable: 'false',
        })
      }
      return e
    })
  }

  function shimMaxMessageSize(window, browserDetails) {
    if (!window.RTCPeerConnection) {
      return
    }

    if (!('sctp' in window.RTCPeerConnection.prototype)) {
      Object.defineProperty(window.RTCPeerConnection.prototype, 'sctp', {
        get() {
          return typeof this._sctp === 'undefined' ? null : this._sctp
        },
      })
    }

    const sctpInDescription = function (description) {
      if (!description || !description.sdp) {
        return false
      }
      const sections = sdp.splitSections(description.sdp)
      sections.shift()
      return sections.some((mediaSection) => {
        const mLine = sdp.parseMLine(mediaSection)
        return mLine && mLine.kind === 'application' && mLine.protocol.indexOf('SCTP') !== -1
      })
    }

    const getRemoteFirefoxVersion = function (description) {
      // TODO: Is there a better solution for detecting Firefox?
      const match = description.sdp.match(/mozilla...THIS_IS_SDPARTA-(\d+)/)
      if (match === null || match.length < 2) {
        return -1
      }
      const version = parseInt(match[1], 10)
      // Test for NaN (yes, this is ugly)
      return version !== version ? -1 : version
    }

    const getCanSendMaxMessageSize = function (remoteIsFirefox) {
      // Every implementation we know can send at least 64 KiB.
      // Note: Although Chrome is technically able to send up to 256 KiB, the
      //       data does not reach the other peer reliably.
      //       See: https://bugs.chromium.org/p/webrtc/issues/detail?id=8419
      let canSendMaxMessageSize = 65536
      if (browserDetails.browser === 'firefox') {
        if (browserDetails.version < 57) {
          if (remoteIsFirefox === -1) {
            // FF < 57 will send in 16 KiB chunks using the deprecated PPID
            // fragmentation.
            canSendMaxMessageSize = 16384
          } else {
            // However, other FF (and RAWRTC) can reassemble PPID-fragmented
            // messages. Thus, supporting ~2 GiB when sending.
            canSendMaxMessageSize = 2147483637
          }
        } else if (browserDetails.version < 60) {
          // Currently, all FF >= 57 will reset the remote maximum message size
          // to the default value when a data channel is created at a later
          // stage. :(
          // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831
          canSendMaxMessageSize = browserDetails.version === 57 ? 65535 : 65536
        } else {
          // FF >= 60 supports sending ~2 GiB
          canSendMaxMessageSize = 2147483637
        }
      }
      return canSendMaxMessageSize
    }

    const getMaxMessageSize = function (description, remoteIsFirefox) {
      // Note: 65536 bytes is the default value from the SDP spec. Also,
      //       every implementation we know supports receiving 65536 bytes.
      let maxMessageSize = 65536

      // FF 57 has a slightly incorrect default remote max message size, so
      // we need to adjust it here to avoid a failure when sending.
      // See: https://bugzilla.mozilla.org/show_bug.cgi?id=1425697
      if (browserDetails.browser === 'firefox' && browserDetails.version === 57) {
        maxMessageSize = 65535
      }

      const match = sdp.matchPrefix(description.sdp, 'a=max-message-size:')
      if (match.length > 0) {
        maxMessageSize = parseInt(match[0].substr(19), 10)
      } else if (browserDetails.browser === 'firefox' && remoteIsFirefox !== -1) {
        // If the maximum message size is not present in the remote SDP and
        // both local and remote are Firefox, the remote peer can receive
        // ~2 GiB.
        maxMessageSize = 2147483637
      }
      return maxMessageSize
    }

    const origSetRemoteDescription = window.RTCPeerConnection.prototype.setRemoteDescription
    window.RTCPeerConnection.prototype.setRemoteDescription = function setRemoteDescription() {
      this._sctp = null
      // Chrome decided to not expose .sctp in plan-b mode.
      // As usual, adapter.js has to do an 'ugly worakaround'
      // to cover up the mess.
      if (browserDetails.browser === 'chrome' && browserDetails.version >= 76) {
        const { sdpSemantics } = this.getConfiguration()
        if (sdpSemantics === 'plan-b') {
          Object.defineProperty(this, 'sctp', {
            get() {
              return typeof this._sctp === 'undefined' ? null : this._sctp
            },
            enumerable: true,
            configurable: true,
          })
        }
      }

      if (sctpInDescription(arguments[0])) {
        // Check if the remote is FF.
        const isFirefox = getRemoteFirefoxVersion(arguments[0])

        // Get the maximum message size the local peer is capable of sending
        const canSendMMS = getCanSendMaxMessageSize(isFirefox)

        // Get the maximum message size of the remote peer.
        const remoteMMS = getMaxMessageSize(arguments[0], isFirefox)

        // Determine final maximum message size
        let maxMessageSize
        if (canSendMMS === 0 && remoteMMS === 0) {
          maxMessageSize = Number.POSITIVE_INFINITY
        } else if (canSendMMS === 0 || remoteMMS === 0) {
          maxMessageSize = Math.max(canSendMMS, remoteMMS)
        } else {
          maxMessageSize = Math.min(canSendMMS, remoteMMS)
        }

        // Create a dummy RTCSctpTransport object and the 'maxMessageSize'
        // attribute.
        const sctp = {}
        Object.defineProperty(sctp, 'maxMessageSize', {
          get() {
            return maxMessageSize
          },
        })
        this._sctp = sctp
      }

      return origSetRemoteDescription.apply(this, arguments)
    }
  }

  function shimSendThrowTypeError(window) {
    if (!(window.RTCPeerConnection && 'createDataChannel' in window.RTCPeerConnection.prototype)) {
      return
    }

    // Note: Although Firefox >= 57 has a native implementation, the maximum
    //       message size can be reset for all data channels at a later stage.
    //       See: https://bugzilla.mozilla.org/show_bug.cgi?id=1426831

    function wrapDcSend(dc, pc) {
      const origDataChannelSend = dc.send
      dc.send = function send() {
        const data = arguments[0]
        const length = data.length || data.size || data.byteLength
        if (dc.readyState === 'open' && pc.sctp && length > pc.sctp.maxMessageSize) {
          throw new TypeError(
            'Message too large (can send a maximum of ' + pc.sctp.maxMessageSize + ' bytes)'
          )
        }
        return origDataChannelSend.apply(dc, arguments)
      }
    }
    const origCreateDataChannel = window.RTCPeerConnection.prototype.createDataChannel
    window.RTCPeerConnection.prototype.createDataChannel = function createDataChannel() {
      const dataChannel = origCreateDataChannel.apply(this, arguments)
      wrapDcSend(dataChannel, this)
      return dataChannel
    }
    wrapPeerConnectionEvent(window, 'datachannel', (e) => {
      wrapDcSend(e.channel, e.target)
      return e
    })
  }

  /* shims RTCConnectionState by pretending it is the same as iceConnectionState.
   * See https://bugs.chromium.org/p/webrtc/issues/detail?id=6145#c12
   * for why this is a valid hack in Chrome. In Firefox it is slightly incorrect
   * since DTLS failures would be hidden. See
   * https://bugzilla.mozilla.org/show_bug.cgi?id=1265827
   * for the Firefox tracking bug.
   */
  function shimConnectionState(window) {
    if (!window.RTCPeerConnection || 'connectionState' in window.RTCPeerConnection.prototype) {
      return
    }
    const proto = window.RTCPeerConnection.prototype
    Object.defineProperty(proto, 'connectionState', {
      get() {
        return (
          {
            completed: 'connected',
            checking: 'connecting',
          }[this.iceConnectionState] || this.iceConnectionState
        )
      },
      enumerable: true,
      configurable: true,
    })
    Object.defineProperty(proto, 'onconnectionstatechange', {
      get() {
        return this._onconnectionstatechange || null
      },
      set(cb) {
        if (this._onconnectionstatechange) {
          this.removeEventListener('connectionstatechange', this._onconnectionstatechange)
          delete this._onconnectionstatechange
        }
        if (cb) {
          this.addEventListener('connectionstatechange', (this._onconnectionstatechange = cb))
        }
      },
      enumerable: true,
      configurable: true,
    })

    ;['setLocalDescription', 'setRemoteDescription'].forEach((method) => {
      const origMethod = proto[method]
      proto[method] = function () {
        if (!this._connectionstatechangepoly) {
          this._connectionstatechangepoly = (e) => {
            const pc = e.target
            if (pc._lastConnectionState !== pc.connectionState) {
              pc._lastConnectionState = pc.connectionState
              const newEvent = new Event('connectionstatechange', e)
              pc.dispatchEvent(newEvent)
            }
            return e
          }
          this.addEventListener('iceconnectionstatechange', this._connectionstatechangepoly)
        }
        return origMethod.apply(this, arguments)
      }
    })
  }

  function removeExtmapAllowMixed(window, browserDetails) {
    /* remove a=extmap-allow-mixed for webrtc.org < M71 */
    if (!window.RTCPeerConnection) {
      return
    }
    if (browserDetails.browser === 'chrome' && browserDetails.version >= 71) {
      return
    }
    if (browserDetails.browser === 'safari' && browserDetails.version >= 605) {
      return
    }
    const nativeSRD = window.RTCPeerConnection.prototype.setRemoteDescription
    window.RTCPeerConnection.prototype.setRemoteDescription = function setRemoteDescription(desc) {
      if (desc && desc.sdp && desc.sdp.indexOf('\na=extmap-allow-mixed') !== -1) {
        const sdp = desc.sdp
          .split('\n')
          .filter((line) => {
            return line.trim() !== 'a=extmap-allow-mixed'
          })
          .join('\n')
        // Safari enforces read-only-ness of RTCSessionDescription fields.
        if (window.RTCSessionDescription && desc instanceof window.RTCSessionDescription) {
          arguments[0] = new window.RTCSessionDescription({
            type: desc.type,
            sdp,
          })
        } else {
          desc.sdp = sdp
        }
      }
      return nativeSRD.apply(this, arguments)
    }
  }

  function shimAddIceCandidateNullOrEmpty(window, browserDetails) {
    // Support for addIceCandidate(null or undefined)
    // as well as addIceCandidate({candidate: "", ...})
    // https://bugs.chromium.org/p/chromium/issues/detail?id=978582
    // Note: must be called before other polyfills which change the signature.
    if (!(window.RTCPeerConnection && window.RTCPeerConnection.prototype)) {
      return
    }
    const nativeAddIceCandidate = window.RTCPeerConnection.prototype.addIceCandidate
    if (!nativeAddIceCandidate || nativeAddIceCandidate.length === 0) {
      return
    }
    window.RTCPeerConnection.prototype.addIceCandidate = function addIceCandidate() {
      if (!arguments[0]) {
        if (arguments[1]) {
          arguments[1].apply(null)
        }
        return Promise.resolve()
      }
      // Firefox 68+ emits and processes {candidate: "", ...}, ignore
      // in older versions.
      // Native support for ignoring exists for Chrome M77+.
      // Safari ignores as well, exact version unknown but works in the same
      // version that also ignores addIceCandidate(null).
      if (
        ((browserDetails.browser === 'chrome' && browserDetails.version < 78) ||
          (browserDetails.browser === 'firefox' && browserDetails.version < 68) ||
          browserDetails.browser === 'safari') &&
        arguments[0] &&
        arguments[0].candidate === ''
      ) {
        return Promise.resolve()
      }
      return nativeAddIceCandidate.apply(this, arguments)
    }
  }

  var commonShim = /*#__PURE__*/ Object.freeze({
    __proto__: null,
    shimRTCIceCandidate: shimRTCIceCandidate,
    shimMaxMessageSize: shimMaxMessageSize,
    shimSendThrowTypeError: shimSendThrowTypeError,
    shimConnectionState: shimConnectionState,
    removeExtmapAllowMixed: removeExtmapAllowMixed,
    shimAddIceCandidateNullOrEmpty: shimAddIceCandidateNullOrEmpty,
  })

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  // Shimming starts here.
  function adapterFactory(
    { window } = {},
    options = {
      shimChrome: true,
      shimFirefox: true,
      shimEdge: true,
      shimSafari: true,
    }
  ) {
    // Utils.
    const logging = log$1
    const browserDetails = detectBrowser(window)

    const adapter = {
      browserDetails,
      commonShim,
      extractVersion: extractVersion,
      disableLog: disableLog,
      disableWarnings: disableWarnings,
    }

    // Shim browser if found.
    switch (browserDetails.browser) {
      case 'chrome':
        if (!chromeShim || !shimPeerConnection$2 || !options.shimChrome) {
          logging('Chrome shim is not included in this adapter release.')
          return adapter
        }
        if (browserDetails.version === null) {
          logging('Chrome shim can not determine version, not shimming.')
          return adapter
        }
        logging('adapter.js shimming chrome.')
        // Export to the adapter global object visible in the browser.
        adapter.browserShim = chromeShim

        // Must be called before shimPeerConnection.
        shimAddIceCandidateNullOrEmpty(window, browserDetails)

        shimGetUserMedia$3(window, browserDetails)
        shimMediaStream(window)
        shimPeerConnection$2(window, browserDetails)
        shimOnTrack$1(window)
        shimAddTrackRemoveTrack(window, browserDetails)
        shimGetSendersWithDtmf(window)
        shimGetStats(window)
        shimSenderReceiverGetStats(window)
        fixNegotiationNeeded(window, browserDetails)

        shimRTCIceCandidate(window)
        shimConnectionState(window)
        shimMaxMessageSize(window, browserDetails)
        shimSendThrowTypeError(window)
        removeExtmapAllowMixed(window, browserDetails)
        break
      case 'firefox':
        if (!firefoxShim || !shimPeerConnection || !options.shimFirefox) {
          logging('Firefox shim is not included in this adapter release.')
          return adapter
        }
        logging('adapter.js shimming firefox.')
        // Export to the adapter global object visible in the browser.
        adapter.browserShim = firefoxShim

        // Must be called before shimPeerConnection.
        shimAddIceCandidateNullOrEmpty(window, browserDetails)

        shimGetUserMedia$1(window, browserDetails)
        shimPeerConnection(window, browserDetails)
        shimOnTrack(window)
        shimRemoveStream(window)
        shimSenderGetStats(window)
        shimReceiverGetStats(window)
        shimRTCDataChannel(window)
        shimAddTransceiver(window)
        shimGetParameters(window)
        shimCreateOffer(window)
        shimCreateAnswer(window)

        shimRTCIceCandidate(window)
        shimConnectionState(window)
        shimMaxMessageSize(window, browserDetails)
        shimSendThrowTypeError(window)
        break
      case 'edge':
        if (!edgeShim || !shimPeerConnection$1 || !options.shimEdge) {
          logging('MS edge shim is not included in this adapter release.')
          return adapter
        }
        logging('adapter.js shimming edge.')
        // Export to the adapter global object visible in the browser.
        adapter.browserShim = edgeShim

        shimGetUserMedia$2(window)
        shimGetDisplayMedia$1(window)
        shimPeerConnection$1(window, browserDetails)
        shimReplaceTrack(window)

        // the edge shim implements the full RTCIceCandidate object.

        shimMaxMessageSize(window, browserDetails)
        shimSendThrowTypeError(window)
        break
      case 'safari':
        if (!safariShim || !options.shimSafari) {
          logging('Safari shim is not included in this adapter release.')
          return adapter
        }
        logging('adapter.js shimming safari.')
        // Export to the adapter global object visible in the browser.
        adapter.browserShim = safariShim

        // Must be called before shimCallbackAPI.
        shimAddIceCandidateNullOrEmpty(window, browserDetails)

        shimRTCIceServerUrls(window)
        shimCreateOfferLegacy(window)
        shimCallbacksAPI(window)
        shimLocalStreamsAPI(window)
        shimRemoteStreamsAPI(window)
        shimTrackEventTransceiver(window)
        shimGetUserMedia(window)
        shimAudioContext(window)

        shimRTCIceCandidate(window)
        shimMaxMessageSize(window, browserDetails)
        shimSendThrowTypeError(window)
        removeExtmapAllowMixed(window, browserDetails)
        break
      default:
        logging('Unsupported browser!')
        break
    }

    return adapter
  }

  /*
   *  Copyright (c) 2016 The WebRTC project authors. All Rights Reserved.
   *
   *  Use of this source code is governed by a BSD-style license
   *  that can be found in the LICENSE file in the root of the source
   *  tree.
   */

  adapterFactory({ window: typeof window === 'undefined' ? undefined : window })

  /**
   * @class AudioTrackConstraints
   * @classDesc Constraints for creating an audio MediaStreamTrack.
   * @memberof Owt.Base
   * @constructor
   * @param {Owt.Base.AudioSourceInfo} source Source info of this audio track.
   */

  class AudioTrackConstraints {
    // eslint-disable-next-line require-jsdoc
    constructor(source) {
      if (!Object.values(AudioSourceInfo).some((v) => v === source)) {
        throw new TypeError('Invalid source.')
      }
      /**
       * @member {string} source
       * @memberof Owt.Base.AudioTrackConstraints
       * @desc Values could be "mic", "screen-cast", "file" or "mixed".
       * @instance
       */

      this.source = source
      /**
       * @member {string} deviceId
       * @memberof Owt.Base.AudioTrackConstraints
       * @desc Do not provide deviceId if source is not "mic".
       * @instance
       * @see https://w3c.github.io/mediacapture-main/#def-constraint-deviceId
       */

      this.deviceId = undefined
    }
  }
  /**
   * @class VideoTrackConstraints
   * @classDesc Constraints for creating a video MediaStreamTrack.
   * @memberof Owt.Base
   * @constructor
   * @param {Owt.Base.VideoSourceInfo} source Source info of this video track.
   */

  class VideoTrackConstraints {
    // eslint-disable-next-line require-jsdoc
    constructor(source) {
      if (!Object.values(VideoSourceInfo).some((v) => v === source)) {
        throw new TypeError('Invalid source.')
      }
      /**
       * @member {string} source
       * @memberof Owt.Base.VideoTrackConstraints
       * @desc Values could be "camera", "screen-cast", "file" or "mixed".
       * @instance
       */

      this.source = source
      /**
       * @member {string} deviceId
       * @memberof Owt.Base.VideoTrackConstraints
       * @desc Do not provide deviceId if source is not "camera".
       * @instance
       * @see https://w3c.github.io/mediacapture-main/#def-constraint-deviceId
       */

      this.deviceId = undefined
      /**
       * @member {Owt.Base.Resolution} resolution
       * @memberof Owt.Base.VideoTrackConstraints
       * @instance
       */

      this.resolution = undefined
      /**
       * @member {number} frameRate
       * @memberof Owt.Base.VideoTrackConstraints
       * @instance
       */

      this.frameRate = undefined
    }
  }
  /**
   * @class StreamConstraints
   * @classDesc Constraints for creating a MediaStream from screen mic and camera.
   * @memberof Owt.Base
   * @constructor
   * @param {?Owt.Base.AudioTrackConstraints} audioConstraints
   * @param {?Owt.Base.VideoTrackConstraints} videoConstraints
   */

  class StreamConstraints {
    // eslint-disable-next-line require-jsdoc
    constructor(audioConstraints = false, videoConstraints = false) {
      /**
       * @member {Owt.Base.MediaStreamTrackDeviceConstraintsForAudio} audio
       * @memberof Owt.Base.MediaStreamDeviceConstraints
       * @instance
       */
      this.audio = audioConstraints
      /**
       * @member {Owt.Base.MediaStreamTrackDeviceConstraintsForVideo} Video
       * @memberof Owt.Base.MediaStreamDeviceConstraints
       * @instance
       */

      this.video = videoConstraints
    }
  } // eslint-disable-next-line require-jsdoc

  function isVideoConstrainsForScreenCast(constraints) {
    return (
      typeof constraints.video === 'object' &&
      constraints.video.source === VideoSourceInfo.SCREENCAST
    )
  }
  /**
   * @class MediaStreamFactory
   * @classDesc A factory to create MediaStream. You can also create MediaStream by yourself.
   * @memberof Owt.Base
   */

  class MediaStreamFactory {
    /**
     * @function createMediaStream
     * @static
     * @desc Create a MediaStream with given constraints. If you want to create a MediaStream for screen cast, please make sure both audio and video's source are "screen-cast".
     * @memberof Owt.Base.MediaStreamFactory
     * @return {Promise<MediaStream, Error>} Return a promise that is resolved when stream is successfully created, or rejected if one of the following error happened:
     * - One or more parameters cannot be satisfied.
     * - Specified device is busy.
     * - Cannot obtain necessary permission or operation is canceled by user.
     * - Video source is screen cast, while audio source is not.
     * - Audio source is screen cast, while video source is disabled.
     * @param {Owt.Base.StreamConstraints} constraints
     */
    static createMediaStream(constraints) {
      if (typeof constraints !== 'object' || (!constraints.audio && !constraints.video)) {
        return Promise.reject(new TypeError('Invalid constrains'))
      }

      if (
        !isVideoConstrainsForScreenCast(constraints) &&
        typeof constraints.audio === 'object' &&
        constraints.audio.source === AudioSourceInfo.SCREENCAST
      ) {
        return Promise.reject(new TypeError('Cannot share screen without video.'))
      }

      if (isVideoConstrainsForScreenCast(constraints) && !isChrome() && !isFirefox()) {
        return Promise.reject(new TypeError('Screen sharing only supports Chrome and Firefox.'))
      }

      if (
        isVideoConstrainsForScreenCast(constraints) &&
        typeof constraints.audio === 'object' &&
        constraints.audio.source !== AudioSourceInfo.SCREENCAST
      ) {
        return Promise.reject(
          new TypeError(
            'Cannot capture video from screen cast while capture audio from' + ' other source.'
          )
        )
      } // Check and convert constraints.

      if (!constraints.audio && !constraints.video) {
        return Promise.reject(new TypeError('At least one of audio and video must be requested.'))
      }

      const mediaConstraints = Object.create({})

      if (
        typeof constraints.audio === 'object' &&
        constraints.audio.source === AudioSourceInfo.MIC
      ) {
        mediaConstraints.audio = Object.create({})

        if (isEdge()) {
          mediaConstraints.audio.deviceId = constraints.audio.deviceId
        } else {
          mediaConstraints.audio.deviceId = {
            exact: constraints.audio.deviceId,
          }
        }
      } else {
        if (constraints.audio.source === AudioSourceInfo.SCREENCAST) {
          mediaConstraints.audio = true
        } else {
          mediaConstraints.audio = constraints.audio
        }
      }

      if (typeof constraints.video === 'object') {
        mediaConstraints.video = Object.create({})

        if (typeof constraints.video.frameRate === 'number') {
          mediaConstraints.video.frameRate = constraints.video.frameRate
        }

        if (
          constraints.video.resolution &&
          constraints.video.resolution.width &&
          constraints.video.resolution.height
        ) {
          if (constraints.video.source === VideoSourceInfo.SCREENCAST) {
            mediaConstraints.video.width = constraints.video.resolution.width
            mediaConstraints.video.height = constraints.video.resolution.height
          } else {
            mediaConstraints.video.width = Object.create({})
            mediaConstraints.video.width.exact = constraints.video.resolution.width
            mediaConstraints.video.height = Object.create({})
            mediaConstraints.video.height.exact = constraints.video.resolution.height
          }
        }

        if (typeof constraints.video.deviceId === 'string') {
          mediaConstraints.video.deviceId = {
            exact: constraints.video.deviceId,
          }
        }

        if (isFirefox() && constraints.video.source === VideoSourceInfo.SCREENCAST) {
          mediaConstraints.video.mediaSource = 'screen'
        }
      } else {
        mediaConstraints.video = constraints.video
      }

      if (isVideoConstrainsForScreenCast(constraints)) {
        return navigator.mediaDevices.getDisplayMedia(mediaConstraints)
      } else {
        return navigator.mediaDevices.getUserMedia(mediaConstraints)
      }
    }
  }

  // Copyright (C) <2018> Intel Corporation

  var media = /*#__PURE__*/ Object.freeze({
    __proto__: null,
    AudioTrackConstraints: AudioTrackConstraints,
    VideoTrackConstraints: VideoTrackConstraints,
    StreamConstraints: StreamConstraints,
    MediaStreamFactory: MediaStreamFactory,
    AudioSourceInfo: AudioSourceInfo,
    VideoSourceInfo: VideoSourceInfo,
    TrackKind: TrackKind,
    Resolution: Resolution,
  })

  let logger
  let errorLogger
  function setLogger() {
    /*eslint-disable */
    logger = console.log
    errorLogger = console.error
    /*eslint-enable */
  }
  function log(message, ...optionalParams) {
    if (logger) {
      logger(message, ...optionalParams)
    }
  }
  function error(message, ...optionalParams) {
    if (errorLogger) {
      errorLogger(message, ...optionalParams)
    }
  }

  class Event$1 {
    constructor(type) {
      this.listener = {}
      this.type = type | ''
    }

    on(event, fn) {
      if (!this.listener[event]) {
        this.listener[event] = []
      }

      this.listener[event].push(fn)
      return true
    }

    off(event, fn) {
      if (this.listener[event]) {
        var index = this.listener[event].indexOf(fn)

        if (index > -1) {
          this.listener[event].splice(index, 1)
        }

        return true
      }

      return false
    }

    offAll() {
      this.listener = {}
    }

    dispatch(event, data) {
      if (this.listener[event]) {
        this.listener[event].map((each) => {
          each.apply(null, [data])
        })
        return true
      }

      return false
    }
  }

  var bind = function bind(fn, thisArg) {
    return function wrap() {
      var args = new Array(arguments.length)
      for (var i = 0; i < args.length; i++) {
        args[i] = arguments[i]
      }
      return fn.apply(thisArg, args)
    }
  }

  /*global toString:true*/

  // utils is a library of generic helper functions non-specific to axios

  var toString = Object.prototype.toString

  /**
   * Determine if a value is an Array
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is an Array, otherwise false
   */
  function isArray(val) {
    return toString.call(val) === '[object Array]'
  }

  /**
   * Determine if a value is undefined
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if the value is undefined, otherwise false
   */
  function isUndefined(val) {
    return typeof val === 'undefined'
  }

  /**
   * Determine if a value is a Buffer
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a Buffer, otherwise false
   */
  function isBuffer(val) {
    return (
      val !== null &&
      !isUndefined(val) &&
      val.constructor !== null &&
      !isUndefined(val.constructor) &&
      typeof val.constructor.isBuffer === 'function' &&
      val.constructor.isBuffer(val)
    )
  }

  /**
   * Determine if a value is an ArrayBuffer
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is an ArrayBuffer, otherwise false
   */
  function isArrayBuffer(val) {
    return toString.call(val) === '[object ArrayBuffer]'
  }

  /**
   * Determine if a value is a FormData
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is an FormData, otherwise false
   */
  function isFormData(val) {
    return typeof FormData !== 'undefined' && val instanceof FormData
  }

  /**
   * Determine if a value is a view on an ArrayBuffer
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a view on an ArrayBuffer, otherwise false
   */
  function isArrayBufferView(val) {
    var result
    if (typeof ArrayBuffer !== 'undefined' && ArrayBuffer.isView) {
      result = ArrayBuffer.isView(val)
    } else {
      result = val && val.buffer && val.buffer instanceof ArrayBuffer
    }
    return result
  }

  /**
   * Determine if a value is a String
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a String, otherwise false
   */
  function isString(val) {
    return typeof val === 'string'
  }

  /**
   * Determine if a value is a Number
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a Number, otherwise false
   */
  function isNumber(val) {
    return typeof val === 'number'
  }

  /**
   * Determine if a value is an Object
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is an Object, otherwise false
   */
  function isObject(val) {
    return val !== null && typeof val === 'object'
  }

  /**
   * Determine if a value is a plain Object
   *
   * @param {Object} val The value to test
   * @return {boolean} True if value is a plain Object, otherwise false
   */
  function isPlainObject(val) {
    if (toString.call(val) !== '[object Object]') {
      return false
    }

    var prototype = Object.getPrototypeOf(val)
    return prototype === null || prototype === Object.prototype
  }

  /**
   * Determine if a value is a Date
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a Date, otherwise false
   */
  function isDate(val) {
    return toString.call(val) === '[object Date]'
  }

  /**
   * Determine if a value is a File
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a File, otherwise false
   */
  function isFile(val) {
    return toString.call(val) === '[object File]'
  }

  /**
   * Determine if a value is a Blob
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a Blob, otherwise false
   */
  function isBlob(val) {
    return toString.call(val) === '[object Blob]'
  }

  /**
   * Determine if a value is a Function
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a Function, otherwise false
   */
  function isFunction(val) {
    return toString.call(val) === '[object Function]'
  }

  /**
   * Determine if a value is a Stream
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a Stream, otherwise false
   */
  function isStream(val) {
    return isObject(val) && isFunction(val.pipe)
  }

  /**
   * Determine if a value is a URLSearchParams object
   *
   * @param {Object} val The value to test
   * @returns {boolean} True if value is a URLSearchParams object, otherwise false
   */
  function isURLSearchParams(val) {
    return typeof URLSearchParams !== 'undefined' && val instanceof URLSearchParams
  }

  /**
   * Trim excess whitespace off the beginning and end of a string
   *
   * @param {String} str The String to trim
   * @returns {String} The String freed of excess whitespace
   */
  function trim(str) {
    return str.replace(/^\s*/, '').replace(/\s*$/, '')
  }

  /**
   * Determine if we're running in a standard browser environment
   *
   * This allows axios to run in a web worker, and react-native.
   * Both environments support XMLHttpRequest, but not fully standard globals.
   *
   * web workers:
   *  typeof window -> undefined
   *  typeof document -> undefined
   *
   * react-native:
   *  navigator.product -> 'ReactNative'
   * nativescript
   *  navigator.product -> 'NativeScript' or 'NS'
   */
  function isStandardBrowserEnv() {
    if (
      typeof navigator !== 'undefined' &&
      (navigator.product === 'ReactNative' ||
        navigator.product === 'NativeScript' ||
        navigator.product === 'NS')
    ) {
      return false
    }
    return typeof window !== 'undefined' && typeof document !== 'undefined'
  }

  /**
   * Iterate over an Array or an Object invoking a function for each item.
   *
   * If `obj` is an Array callback will be called passing
   * the value, index, and complete array for each item.
   *
   * If 'obj' is an Object callback will be called passing
   * the value, key, and complete object for each property.
   *
   * @param {Object|Array} obj The object to iterate
   * @param {Function} fn The callback to invoke for each item
   */
  function forEach(obj, fn) {
    // Don't bother if no value provided
    if (obj === null || typeof obj === 'undefined') {
      return
    }

    // Force an array if not already something iterable
    if (typeof obj !== 'object') {
      /*eslint no-param-reassign:0*/
      obj = [obj]
    }

    if (isArray(obj)) {
      // Iterate over array values
      for (var i = 0, l = obj.length; i < l; i++) {
        fn.call(null, obj[i], i, obj)
      }
    } else {
      // Iterate over object keys
      for (var key in obj) {
        if (Object.prototype.hasOwnProperty.call(obj, key)) {
          fn.call(null, obj[key], key, obj)
        }
      }
    }
  }

  /**
   * Accepts varargs expecting each argument to be an object, then
   * immutably merges the properties of each object and returns result.
   *
   * When multiple objects contain the same key the later object in
   * the arguments list will take precedence.
   *
   * Example:
   *
   * ```js
   * var result = merge({foo: 123}, {foo: 456});
   * console.log(result.foo); // outputs 456
   * ```
   *
   * @param {Object} obj1 Object to merge
   * @returns {Object} Result of all merge properties
   */
  function merge(/* obj1, obj2, obj3, ... */) {
    var result = {}
    function assignValue(val, key) {
      if (isPlainObject(result[key]) && isPlainObject(val)) {
        result[key] = merge(result[key], val)
      } else if (isPlainObject(val)) {
        result[key] = merge({}, val)
      } else if (isArray(val)) {
        result[key] = val.slice()
      } else {
        result[key] = val
      }
    }

    for (var i = 0, l = arguments.length; i < l; i++) {
      forEach(arguments[i], assignValue)
    }
    return result
  }

  /**
   * Extends object a by mutably adding to it the properties of object b.
   *
   * @param {Object} a The object to be extended
   * @param {Object} b The object to copy properties from
   * @param {Object} thisArg The object to bind function to
   * @return {Object} The resulting value of object a
   */
  function extend(a, b, thisArg) {
    forEach(b, function assignValue(val, key) {
      if (thisArg && typeof val === 'function') {
        a[key] = bind(val, thisArg)
      } else {
        a[key] = val
      }
    })
    return a
  }

  /**
   * Remove byte order marker. This catches EF BB BF (the UTF-8 BOM)
   *
   * @param {string} content with BOM
   * @return {string} content value without BOM
   */
  function stripBOM(content) {
    if (content.charCodeAt(0) === 0xfeff) {
      content = content.slice(1)
    }
    return content
  }

  var utils = {
    isArray: isArray,
    isArrayBuffer: isArrayBuffer,
    isBuffer: isBuffer,
    isFormData: isFormData,
    isArrayBufferView: isArrayBufferView,
    isString: isString,
    isNumber: isNumber,
    isObject: isObject,
    isPlainObject: isPlainObject,
    isUndefined: isUndefined,
    isDate: isDate,
    isFile: isFile,
    isBlob: isBlob,
    isFunction: isFunction,
    isStream: isStream,
    isURLSearchParams: isURLSearchParams,
    isStandardBrowserEnv: isStandardBrowserEnv,
    forEach: forEach,
    merge: merge,
    extend: extend,
    trim: trim,
    stripBOM: stripBOM,
  }

  function encode(val) {
    return encodeURIComponent(val)
      .replace(/%3A/gi, ':')
      .replace(/%24/g, '$')
      .replace(/%2C/gi, ',')
      .replace(/%20/g, '+')
      .replace(/%5B/gi, '[')
      .replace(/%5D/gi, ']')
  }

  /**
   * Build a URL by appending params to the end
   *
   * @param {string} url The base of the url (e.g., http://www.google.com)
   * @param {object} [params] The params to be appended
   * @returns {string} The formatted url
   */
  var buildURL = function buildURL(url, params, paramsSerializer) {
    /*eslint no-param-reassign:0*/
    if (!params) {
      return url
    }

    var serializedParams
    if (paramsSerializer) {
      serializedParams = paramsSerializer(params)
    } else if (utils.isURLSearchParams(params)) {
      serializedParams = params.toString()
    } else {
      var parts = []

      utils.forEach(params, function serialize(val, key) {
        if (val === null || typeof val === 'undefined') {
          return
        }

        if (utils.isArray(val)) {
          key = key + '[]'
        } else {
          val = [val]
        }

        utils.forEach(val, function parseValue(v) {
          if (utils.isDate(v)) {
            v = v.toISOString()
          } else if (utils.isObject(v)) {
            v = JSON.stringify(v)
          }
          parts.push(encode(key) + '=' + encode(v))
        })
      })

      serializedParams = parts.join('&')
    }

    if (serializedParams) {
      var hashmarkIndex = url.indexOf('#')
      if (hashmarkIndex !== -1) {
        url = url.slice(0, hashmarkIndex)
      }

      url += (url.indexOf('?') === -1 ? '?' : '&') + serializedParams
    }

    return url
  }

  function InterceptorManager() {
    this.handlers = []
  }

  /**
   * Add a new interceptor to the stack
   *
   * @param {Function} fulfilled The function to handle `then` for a `Promise`
   * @param {Function} rejected The function to handle `reject` for a `Promise`
   *
   * @return {Number} An ID used to remove interceptor later
   */
  InterceptorManager.prototype.use = function use(fulfilled, rejected) {
    this.handlers.push({
      fulfilled: fulfilled,
      rejected: rejected,
    })
    return this.handlers.length - 1
  }

  /**
   * Remove an interceptor from the stack
   *
   * @param {Number} id The ID that was returned by `use`
   */
  InterceptorManager.prototype.eject = function eject(id) {
    if (this.handlers[id]) {
      this.handlers[id] = null
    }
  }

  /**
   * Iterate over all the registered interceptors
   *
   * This method is particularly useful for skipping over any
   * interceptors that may have become `null` calling `eject`.
   *
   * @param {Function} fn The function to call for each interceptor
   */
  InterceptorManager.prototype.forEach = function forEach(fn) {
    utils.forEach(this.handlers, function forEachHandler(h) {
      if (h !== null) {
        fn(h)
      }
    })
  }

  var InterceptorManager_1 = InterceptorManager

  /**
   * Transform the data for a request or a response
   *
   * @param {Object|String} data The data to be transformed
   * @param {Array} headers The headers for the request or response
   * @param {Array|Function} fns A single function or Array of functions
   * @returns {*} The resulting transformed data
   */
  var transformData = function transformData(data, headers, fns) {
    /*eslint no-param-reassign:0*/
    utils.forEach(fns, function transform(fn) {
      data = fn(data, headers)
    })

    return data
  }

  var isCancel = function isCancel(value) {
    return !!(value && value.__CANCEL__)
  }

  var normalizeHeaderName = function normalizeHeaderName(headers, normalizedName) {
    utils.forEach(headers, function processHeader(value, name) {
      if (name !== normalizedName && name.toUpperCase() === normalizedName.toUpperCase()) {
        headers[normalizedName] = value
        delete headers[name]
      }
    })
  }

  /**
   * Update an Error with the specified config, error code, and response.
   *
   * @param {Error} error The error to update.
   * @param {Object} config The config.
   * @param {string} [code] The error code (for example, 'ECONNABORTED').
   * @param {Object} [request] The request.
   * @param {Object} [response] The response.
   * @returns {Error} The error.
   */
  var enhanceError = function enhanceError(error, config, code, request, response) {
    error.config = config
    if (code) {
      error.code = code
    }

    error.request = request
    error.response = response
    error.isAxiosError = true

    error.toJSON = function toJSON() {
      return {
        // Standard
        message: this.message,
        name: this.name,
        // Microsoft
        description: this.description,
        number: this.number,
        // Mozilla
        fileName: this.fileName,
        lineNumber: this.lineNumber,
        columnNumber: this.columnNumber,
        stack: this.stack,
        // Axios
        config: this.config,
        code: this.code,
      }
    }
    return error
  }

  /**
   * Create an Error with the specified message, config, error code, request and response.
   *
   * @param {string} message The error message.
   * @param {Object} config The config.
   * @param {string} [code] The error code (for example, 'ECONNABORTED').
   * @param {Object} [request] The request.
   * @param {Object} [response] The response.
   * @returns {Error} The created error.
   */
  var createError = function createError(message, config, code, request, response) {
    var error = new Error(message)
    return enhanceError(error, config, code, request, response)
  }

  /**
   * Resolve or reject a Promise based on response status.
   *
   * @param {Function} resolve A function that resolves the promise.
   * @param {Function} reject A function that rejects the promise.
   * @param {object} response The response.
   */
  var settle = function settle(resolve, reject, response) {
    var validateStatus = response.config.validateStatus
    if (!response.status || !validateStatus || validateStatus(response.status)) {
      resolve(response)
    } else {
      reject(
        createError(
          'Request failed with status code ' + response.status,
          response.config,
          null,
          response.request,
          response
        )
      )
    }
  }

  var cookies = utils.isStandardBrowserEnv()
    ? // Standard browser envs support document.cookie
      (function standardBrowserEnv() {
        return {
          write: function write(name, value, expires, path, domain, secure) {
            var cookie = []
            cookie.push(name + '=' + encodeURIComponent(value))

            if (utils.isNumber(expires)) {
              cookie.push('expires=' + new Date(expires).toGMTString())
            }

            if (utils.isString(path)) {
              cookie.push('path=' + path)
            }

            if (utils.isString(domain)) {
              cookie.push('domain=' + domain)
            }

            if (secure === true) {
              cookie.push('secure')
            }

            document.cookie = cookie.join('; ')
          },

          read: function read(name) {
            var match = document.cookie.match(new RegExp('(^|;\\s*)(' + name + ')=([^;]*)'))
            return match ? decodeURIComponent(match[3]) : null
          },

          remove: function remove(name) {
            this.write(name, '', Date.now() - 86400000)
          },
        }
      })()
    : // Non standard browser env (web workers, react-native) lack needed support.
      (function nonStandardBrowserEnv() {
        return {
          write: function write() {},
          read: function read() {
            return null
          },
          remove: function remove() {},
        }
      })()

  /**
   * Determines whether the specified URL is absolute
   *
   * @param {string} url The URL to test
   * @returns {boolean} True if the specified URL is absolute, otherwise false
   */
  var isAbsoluteURL = function isAbsoluteURL(url) {
    // A URL is considered absolute if it begins with "<scheme>://" or "//" (protocol-relative URL).
    // RFC 3986 defines scheme name as a sequence of characters beginning with a letter and followed
    // by any combination of letters, digits, plus, period, or hyphen.
    return /^([a-z][a-z\d\+\-\.]*:)?\/\//i.test(url)
  }

  /**
   * Creates a new URL by combining the specified URLs
   *
   * @param {string} baseURL The base URL
   * @param {string} relativeURL The relative URL
   * @returns {string} The combined URL
   */
  var combineURLs = function combineURLs(baseURL, relativeURL) {
    return relativeURL
      ? baseURL.replace(/\/+$/, '') + '/' + relativeURL.replace(/^\/+/, '')
      : baseURL
  }

  /**
   * Creates a new URL by combining the baseURL with the requestedURL,
   * only when the requestedURL is not already an absolute URL.
   * If the requestURL is absolute, this function returns the requestedURL untouched.
   *
   * @param {string} baseURL The base URL
   * @param {string} requestedURL Absolute or relative URL to combine
   * @returns {string} The combined full path
   */
  var buildFullPath = function buildFullPath(baseURL, requestedURL) {
    if (baseURL && !isAbsoluteURL(requestedURL)) {
      return combineURLs(baseURL, requestedURL)
    }
    return requestedURL
  }

  // Headers whose duplicates are ignored by node
  // c.f. https://nodejs.org/api/http.html#http_message_headers
  var ignoreDuplicateOf = [
    'age',
    'authorization',
    'content-length',
    'content-type',
    'etag',
    'expires',
    'from',
    'host',
    'if-modified-since',
    'if-unmodified-since',
    'last-modified',
    'location',
    'max-forwards',
    'proxy-authorization',
    'referer',
    'retry-after',
    'user-agent',
  ]

  /**
   * Parse headers into an object
   *
   * ```
   * Date: Wed, 27 Aug 2014 08:58:49 GMT
   * Content-Type: application/json
   * Connection: keep-alive
   * Transfer-Encoding: chunked
   * ```
   *
   * @param {String} headers Headers needing to be parsed
   * @returns {Object} Headers parsed into an object
   */
  var parseHeaders = function parseHeaders(headers) {
    var parsed = {}
    var key
    var val
    var i

    if (!headers) {
      return parsed
    }

    utils.forEach(headers.split('\n'), function parser(line) {
      i = line.indexOf(':')
      key = utils.trim(line.substr(0, i)).toLowerCase()
      val = utils.trim(line.substr(i + 1))

      if (key) {
        if (parsed[key] && ignoreDuplicateOf.indexOf(key) >= 0) {
          return
        }
        if (key === 'set-cookie') {
          parsed[key] = (parsed[key] ? parsed[key] : []).concat([val])
        } else {
          parsed[key] = parsed[key] ? parsed[key] + ', ' + val : val
        }
      }
    })

    return parsed
  }

  var isURLSameOrigin = utils.isStandardBrowserEnv()
    ? // Standard browser envs have full support of the APIs needed to test
      // whether the request URL is of the same origin as current location.
      (function standardBrowserEnv() {
        var msie = /(msie|trident)/i.test(navigator.userAgent)
        var urlParsingNode = document.createElement('a')
        var originURL

        /**
         * Parse a URL to discover it's components
         *
         * @param {String} url The URL to be parsed
         * @returns {Object}
         */
        function resolveURL(url) {
          var href = url

          if (msie) {
            // IE needs attribute set twice to normalize properties
            urlParsingNode.setAttribute('href', href)
            href = urlParsingNode.href
          }

          urlParsingNode.setAttribute('href', href)

          // urlParsingNode provides the UrlUtils interface - http://url.spec.whatwg.org/#urlutils
          return {
            href: urlParsingNode.href,
            protocol: urlParsingNode.protocol ? urlParsingNode.protocol.replace(/:$/, '') : '',
            host: urlParsingNode.host,
            search: urlParsingNode.search ? urlParsingNode.search.replace(/^\?/, '') : '',
            hash: urlParsingNode.hash ? urlParsingNode.hash.replace(/^#/, '') : '',
            hostname: urlParsingNode.hostname,
            port: urlParsingNode.port,
            pathname:
              urlParsingNode.pathname.charAt(0) === '/'
                ? urlParsingNode.pathname
                : '/' + urlParsingNode.pathname,
          }
        }

        originURL = resolveURL(window.location.href)

        /**
         * Determine if a URL shares the same origin as the current location
         *
         * @param {String} requestURL The URL to test
         * @returns {boolean} True if URL shares the same origin, otherwise false
         */
        return function isURLSameOrigin(requestURL) {
          var parsed = utils.isString(requestURL) ? resolveURL(requestURL) : requestURL
          return parsed.protocol === originURL.protocol && parsed.host === originURL.host
        }
      })()
    : // Non standard browser envs (web workers, react-native) lack needed support.
      (function nonStandardBrowserEnv() {
        return function isURLSameOrigin() {
          return true
        }
      })()

  var xhr = function xhrAdapter(config) {
    return new Promise(function dispatchXhrRequest(resolve, reject) {
      var requestData = config.data
      var requestHeaders = config.headers

      if (utils.isFormData(requestData)) {
        delete requestHeaders['Content-Type'] // Let the browser set it
      }

      var request = new XMLHttpRequest()

      // HTTP basic authentication
      if (config.auth) {
        var username = config.auth.username || ''
        var password = config.auth.password
          ? unescape(encodeURIComponent(config.auth.password))
          : ''
        requestHeaders.Authorization = 'Basic ' + btoa(username + ':' + password)
      }

      var fullPath = buildFullPath(config.baseURL, config.url)
      request.open(
        config.method.toUpperCase(),
        buildURL(fullPath, config.params, config.paramsSerializer),
        true
      )

      // Set the request timeout in MS
      request.timeout = config.timeout

      // Listen for ready state
      request.onreadystatechange = function handleLoad() {
        if (!request || request.readyState !== 4) {
          return
        }

        // The request errored out and we didn't get a response, this will be
        // handled by onerror instead
        // With one exception: request that using file: protocol, most browsers
        // will return status as 0 even though it's a successful request
        if (
          request.status === 0 &&
          !(request.responseURL && request.responseURL.indexOf('file:') === 0)
        ) {
          return
        }

        // Prepare the response
        var responseHeaders =
          'getAllResponseHeaders' in request ? parseHeaders(request.getAllResponseHeaders()) : null
        var responseData =
          !config.responseType || config.responseType === 'text'
            ? request.responseText
            : request.response
        var response = {
          data: responseData,
          status: request.status,
          statusText: request.statusText,
          headers: responseHeaders,
          config: config,
          request: request,
        }

        settle(resolve, reject, response)

        // Clean up request
        request = null
      }

      // Handle browser request cancellation (as opposed to a manual cancellation)
      request.onabort = function handleAbort() {
        if (!request) {
          return
        }

        reject(createError('Request aborted', config, 'ECONNABORTED', request))

        // Clean up request
        request = null
      }

      // Handle low level network errors
      request.onerror = function handleError() {
        // Real errors are hidden from us by the browser
        // onerror should only fire if it's a network error
        reject(createError('Network Error', config, null, request))

        // Clean up request
        request = null
      }

      // Handle timeout
      request.ontimeout = function handleTimeout() {
        var timeoutErrorMessage = 'timeout of ' + config.timeout + 'ms exceeded'
        if (config.timeoutErrorMessage) {
          timeoutErrorMessage = config.timeoutErrorMessage
        }
        reject(createError(timeoutErrorMessage, config, 'ECONNABORTED', request))

        // Clean up request
        request = null
      }

      // Add xsrf header
      // This is only done if running in a standard browser environment.
      // Specifically not if we're in a web worker, or react-native.
      if (utils.isStandardBrowserEnv()) {
        // Add xsrf header
        var xsrfValue =
          (config.withCredentials || isURLSameOrigin(fullPath)) && config.xsrfCookieName
            ? cookies.read(config.xsrfCookieName)
            : undefined

        if (xsrfValue) {
          requestHeaders[config.xsrfHeaderName] = xsrfValue
        }
      }

      // Add headers to the request
      if ('setRequestHeader' in request) {
        utils.forEach(requestHeaders, function setRequestHeader(val, key) {
          if (typeof requestData === 'undefined' && key.toLowerCase() === 'content-type') {
            // Remove Content-Type if data is undefined
            delete requestHeaders[key]
          } else {
            // Otherwise add header to the request
            request.setRequestHeader(key, val)
          }
        })
      }

      // Add withCredentials to request if needed
      if (!utils.isUndefined(config.withCredentials)) {
        request.withCredentials = !!config.withCredentials
      }

      // Add responseType to request if needed
      if (config.responseType) {
        try {
          request.responseType = config.responseType
        } catch (e) {
          // Expected DOMException thrown by browsers not compatible XMLHttpRequest Level 2.
          // But, this can be suppressed for 'json' type as it can be parsed by default 'transformResponse' function.
          if (config.responseType !== 'json') {
            throw e
          }
        }
      }

      // Handle progress if needed
      if (typeof config.onDownloadProgress === 'function') {
        request.addEventListener('progress', config.onDownloadProgress)
      }

      // Not all browsers support upload events
      if (typeof config.onUploadProgress === 'function' && request.upload) {
        request.upload.addEventListener('progress', config.onUploadProgress)
      }

      if (config.cancelToken) {
        // Handle cancellation
        config.cancelToken.promise.then(function onCanceled(cancel) {
          if (!request) {
            return
          }

          request.abort()
          reject(cancel)
          // Clean up request
          request = null
        })
      }

      if (!requestData) {
        requestData = null
      }

      // Send the request
      request.send(requestData)
    })
  }

  var DEFAULT_CONTENT_TYPE = {
    'Content-Type': 'application/x-www-form-urlencoded',
  }

  function setContentTypeIfUnset(headers, value) {
    if (!utils.isUndefined(headers) && utils.isUndefined(headers['Content-Type'])) {
      headers['Content-Type'] = value
    }
  }

  function getDefaultAdapter() {
    var adapter
    if (typeof XMLHttpRequest !== 'undefined') {
      // For browsers use XHR adapter
      adapter = xhr
    } else if (
      typeof process !== 'undefined' &&
      Object.prototype.toString.call(process) === '[object process]'
    ) {
      // For node use HTTP adapter
      adapter = xhr
    }
    return adapter
  }

  var defaults = {
    adapter: getDefaultAdapter(),

    transformRequest: [
      function transformRequest(data, headers) {
        normalizeHeaderName(headers, 'Accept')
        normalizeHeaderName(headers, 'Content-Type')
        if (
          utils.isFormData(data) ||
          utils.isArrayBuffer(data) ||
          utils.isBuffer(data) ||
          utils.isStream(data) ||
          utils.isFile(data) ||
          utils.isBlob(data)
        ) {
          return data
        }
        if (utils.isArrayBufferView(data)) {
          return data.buffer
        }
        if (utils.isURLSearchParams(data)) {
          setContentTypeIfUnset(headers, 'application/x-www-form-urlencoded;charset=utf-8')
          return data.toString()
        }
        if (utils.isObject(data)) {
          setContentTypeIfUnset(headers, 'application/json;charset=utf-8')
          return JSON.stringify(data)
        }
        return data
      },
    ],

    transformResponse: [
      function transformResponse(data) {
        /*eslint no-param-reassign:0*/
        if (typeof data === 'string') {
          try {
            data = JSON.parse(data)
          } catch (e) {
            /* Ignore */
          }
        }
        return data
      },
    ],

    /**
     * A timeout in milliseconds to abort a request. If set to 0 (default) a
     * timeout is not created.
     */
    timeout: 0,

    xsrfCookieName: 'XSRF-TOKEN',
    xsrfHeaderName: 'X-XSRF-TOKEN',

    maxContentLength: -1,
    maxBodyLength: -1,

    validateStatus: function validateStatus(status) {
      return status >= 200 && status < 300
    },
  }

  defaults.headers = {
    common: {
      Accept: 'application/json, text/plain, */*',
    },
  }

  utils.forEach(['delete', 'get', 'head'], function forEachMethodNoData(method) {
    defaults.headers[method] = {}
  })

  utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
    defaults.headers[method] = utils.merge(DEFAULT_CONTENT_TYPE)
  })

  var defaults_1 = defaults

  /**
   * Throws a `Cancel` if cancellation has been requested.
   */
  function throwIfCancellationRequested(config) {
    if (config.cancelToken) {
      config.cancelToken.throwIfRequested()
    }
  }

  /**
   * Dispatch a request to the server using the configured adapter.
   *
   * @param {object} config The config that is to be used for the request
   * @returns {Promise} The Promise to be fulfilled
   */
  var dispatchRequest = function dispatchRequest(config) {
    throwIfCancellationRequested(config)

    // Ensure headers exist
    config.headers = config.headers || {}

    // Transform request data
    config.data = transformData(config.data, config.headers, config.transformRequest)

    // Flatten headers
    config.headers = utils.merge(
      config.headers.common || {},
      config.headers[config.method] || {},
      config.headers
    )

    utils.forEach(
      ['delete', 'get', 'head', 'post', 'put', 'patch', 'common'],
      function cleanHeaderConfig(method) {
        delete config.headers[method]
      }
    )

    var adapter = config.adapter || defaults_1.adapter

    return adapter(config).then(
      function onAdapterResolution(response) {
        throwIfCancellationRequested(config)

        // Transform response data
        response.data = transformData(response.data, response.headers, config.transformResponse)

        return response
      },
      function onAdapterRejection(reason) {
        if (!isCancel(reason)) {
          throwIfCancellationRequested(config)

          // Transform response data
          if (reason && reason.response) {
            reason.response.data = transformData(
              reason.response.data,
              reason.response.headers,
              config.transformResponse
            )
          }
        }

        return Promise.reject(reason)
      }
    )
  }

  /**
   * Config-specific merge-function which creates a new config-object
   * by merging two configuration objects together.
   *
   * @param {Object} config1
   * @param {Object} config2
   * @returns {Object} New object resulting from merging config2 to config1
   */
  var mergeConfig = function mergeConfig(config1, config2) {
    // eslint-disable-next-line no-param-reassign
    config2 = config2 || {}
    var config = {}

    var valueFromConfig2Keys = ['url', 'method', 'data']
    var mergeDeepPropertiesKeys = ['headers', 'auth', 'proxy', 'params']
    var defaultToConfig2Keys = [
      'baseURL',
      'transformRequest',
      'transformResponse',
      'paramsSerializer',
      'timeout',
      'timeoutMessage',
      'withCredentials',
      'adapter',
      'responseType',
      'xsrfCookieName',
      'xsrfHeaderName',
      'onUploadProgress',
      'onDownloadProgress',
      'decompress',
      'maxContentLength',
      'maxBodyLength',
      'maxRedirects',
      'transport',
      'httpAgent',
      'httpsAgent',
      'cancelToken',
      'socketPath',
      'responseEncoding',
    ]
    var directMergeKeys = ['validateStatus']

    function getMergedValue(target, source) {
      if (utils.isPlainObject(target) && utils.isPlainObject(source)) {
        return utils.merge(target, source)
      } else if (utils.isPlainObject(source)) {
        return utils.merge({}, source)
      } else if (utils.isArray(source)) {
        return source.slice()
      }
      return source
    }

    function mergeDeepProperties(prop) {
      if (!utils.isUndefined(config2[prop])) {
        config[prop] = getMergedValue(config1[prop], config2[prop])
      } else if (!utils.isUndefined(config1[prop])) {
        config[prop] = getMergedValue(undefined, config1[prop])
      }
    }

    utils.forEach(valueFromConfig2Keys, function valueFromConfig2(prop) {
      if (!utils.isUndefined(config2[prop])) {
        config[prop] = getMergedValue(undefined, config2[prop])
      }
    })

    utils.forEach(mergeDeepPropertiesKeys, mergeDeepProperties)

    utils.forEach(defaultToConfig2Keys, function defaultToConfig2(prop) {
      if (!utils.isUndefined(config2[prop])) {
        config[prop] = getMergedValue(undefined, config2[prop])
      } else if (!utils.isUndefined(config1[prop])) {
        config[prop] = getMergedValue(undefined, config1[prop])
      }
    })

    utils.forEach(directMergeKeys, function merge(prop) {
      if (prop in config2) {
        config[prop] = getMergedValue(config1[prop], config2[prop])
      } else if (prop in config1) {
        config[prop] = getMergedValue(undefined, config1[prop])
      }
    })

    var axiosKeys = valueFromConfig2Keys
      .concat(mergeDeepPropertiesKeys)
      .concat(defaultToConfig2Keys)
      .concat(directMergeKeys)

    var otherKeys = Object.keys(config1)
      .concat(Object.keys(config2))
      .filter(function filterAxiosKeys(key) {
        return axiosKeys.indexOf(key) === -1
      })

    utils.forEach(otherKeys, mergeDeepProperties)

    return config
  }

  /**
   * Create a new instance of Axios
   *
   * @param {Object} instanceConfig The default config for the instance
   */
  function Axios(instanceConfig) {
    this.defaults = instanceConfig
    this.interceptors = {
      request: new InterceptorManager_1(),
      response: new InterceptorManager_1(),
    }
  }

  /**
   * Dispatch a request
   *
   * @param {Object} config The config specific for this request (merged with this.defaults)
   */
  Axios.prototype.request = function request(config) {
    /*eslint no-param-reassign:0*/
    // Allow for axios('example/url'[, config]) a la fetch API
    if (typeof config === 'string') {
      config = arguments[1] || {}
      config.url = arguments[0]
    } else {
      config = config || {}
    }

    config = mergeConfig(this.defaults, config)

    // Set config.method
    if (config.method) {
      config.method = config.method.toLowerCase()
    } else if (this.defaults.method) {
      config.method = this.defaults.method.toLowerCase()
    } else {
      config.method = 'get'
    }

    // Hook up interceptors middleware
    var chain = [dispatchRequest, undefined]
    var promise = Promise.resolve(config)

    this.interceptors.request.forEach(function unshiftRequestInterceptors(interceptor) {
      chain.unshift(interceptor.fulfilled, interceptor.rejected)
    })

    this.interceptors.response.forEach(function pushResponseInterceptors(interceptor) {
      chain.push(interceptor.fulfilled, interceptor.rejected)
    })

    while (chain.length) {
      promise = promise.then(chain.shift(), chain.shift())
    }

    return promise
  }

  Axios.prototype.getUri = function getUri(config) {
    config = mergeConfig(this.defaults, config)
    return buildURL(config.url, config.params, config.paramsSerializer).replace(/^\?/, '')
  }

  // Provide aliases for supported request methods
  utils.forEach(['delete', 'get', 'head', 'options'], function forEachMethodNoData(method) {
    /*eslint func-names:0*/
    Axios.prototype[method] = function (url, config) {
      return this.request(
        mergeConfig(config || {}, {
          method: method,
          url: url,
          data: (config || {}).data,
        })
      )
    }
  })

  utils.forEach(['post', 'put', 'patch'], function forEachMethodWithData(method) {
    /*eslint func-names:0*/
    Axios.prototype[method] = function (url, data, config) {
      return this.request(
        mergeConfig(config || {}, {
          method: method,
          url: url,
          data: data,
        })
      )
    }
  })

  var Axios_1 = Axios

  /**
   * A `Cancel` is an object that is thrown when an operation is canceled.
   *
   * @class
   * @param {string=} message The message.
   */
  function Cancel(message) {
    this.message = message
  }

  Cancel.prototype.toString = function toString() {
    return 'Cancel' + (this.message ? ': ' + this.message : '')
  }

  Cancel.prototype.__CANCEL__ = true

  var Cancel_1 = Cancel

  /**
   * A `CancelToken` is an object that can be used to request cancellation of an operation.
   *
   * @class
   * @param {Function} executor The executor function.
   */
  function CancelToken(executor) {
    if (typeof executor !== 'function') {
      throw new TypeError('executor must be a function.')
    }

    var resolvePromise
    this.promise = new Promise(function promiseExecutor(resolve) {
      resolvePromise = resolve
    })

    var token = this
    executor(function cancel(message) {
      if (token.reason) {
        // Cancellation has already been requested
        return
      }

      token.reason = new Cancel_1(message)
      resolvePromise(token.reason)
    })
  }

  /**
   * Throws a `Cancel` if cancellation has been requested.
   */
  CancelToken.prototype.throwIfRequested = function throwIfRequested() {
    if (this.reason) {
      throw this.reason
    }
  }

  /**
   * Returns an object that contains a new `CancelToken` and a function that, when called,
   * cancels the `CancelToken`.
   */
  CancelToken.source = function source() {
    var cancel
    var token = new CancelToken(function executor(c) {
      cancel = c
    })
    return {
      token: token,
      cancel: cancel,
    }
  }

  var CancelToken_1 = CancelToken

  /**
   * Syntactic sugar for invoking a function and expanding an array for arguments.
   *
   * Common use case would be to use `Function.prototype.apply`.
   *
   *  ```js
   *  function f(x, y, z) {}
   *  var args = [1, 2, 3];
   *  f.apply(null, args);
   *  ```
   *
   * With `spread` this example can be re-written.
   *
   *  ```js
   *  spread(function(x, y, z) {})([1, 2, 3]);
   *  ```
   *
   * @param {Function} callback
   * @returns {Function}
   */
  var spread = function spread(callback) {
    return function wrap(arr) {
      return callback.apply(null, arr)
    }
  }

  /**
   * Determines whether the payload is an error thrown by Axios
   *
   * @param {*} payload The value to test
   * @returns {boolean} True if the payload is an error thrown by Axios, otherwise false
   */
  var isAxiosError = function isAxiosError(payload) {
    return typeof payload === 'object' && payload.isAxiosError === true
  }

  /**
   * Create an instance of Axios
   *
   * @param {Object} defaultConfig The default config for the instance
   * @return {Axios} A new instance of Axios
   */
  function createInstance(defaultConfig) {
    var context = new Axios_1(defaultConfig)
    var instance = bind(Axios_1.prototype.request, context)

    // Copy axios.prototype to instance
    utils.extend(instance, Axios_1.prototype, context)

    // Copy context to instance
    utils.extend(instance, context)

    return instance
  }

  // Create the default instance to be exported
  var axios$1 = createInstance(defaults_1)

  // Expose Axios class to allow class inheritance
  axios$1.Axios = Axios_1

  // Factory for creating new instances
  axios$1.create = function create(instanceConfig) {
    return createInstance(mergeConfig(axios$1.defaults, instanceConfig))
  }

  // Expose Cancel & CancelToken
  axios$1.Cancel = Cancel_1
  axios$1.CancelToken = CancelToken_1
  axios$1.isCancel = isCancel

  // Expose all/spread
  axios$1.all = function all(promises) {
    return Promise.all(promises)
  }
  axios$1.spread = spread

  // Expose isAxiosError
  axios$1.isAxiosError = isAxiosError

  var axios_1 = axios$1

  // Allow use of default import syntax in TypeScript
  var _default = axios$1
  axios_1.default = _default

  var axios = axios_1

  class RTCEndpoint extends Event$1 {
    constructor(options) {
      super('RTCPusherPlayer')
      this.TAG = '[RTCPusherPlayer]'
      let defaults = {
        element: '',
        // html video element
        debug: false,
        // if output debug log
        zlmsdpUrl: '',
        simulcast: false,
        useCamera: true,
        audioEnable: true,
        videoEnable: true,
        recvOnly: false,
        resolution: {
          w: 0,
          h: 0,
        },
      }
      this.options = Object.assign({}, defaults, options)

      if (this.options.debug) {
        setLogger()
      }

      this.e = {
        onicecandidate: this._onIceCandidate.bind(this),
        ontrack: this._onTrack.bind(this),
        onicecandidateerror: this._onIceCandidateError.bind(this),
        onconnectionstatechange: this._onconnectionstatechange.bind(this),
      }
      this._remoteStream = null
      this._localStream = null
      this.pc = new RTCPeerConnection(null)
      this.pc.onicecandidate = this.e.onicecandidate
      this.pc.onicecandidateerror = this.e.onicecandidateerror
      this.pc.ontrack = this.e.ontrack
      this.pc.onconnectionstatechange = this.e.onconnectionstatechange
      if (!this.options.recvOnly && (this.options.audioEnable || this.options.videoEnable))
        this.start()
      else this.receive()
    }

    receive() {
      const AudioTransceiverInit = {
        direction: 'recvonly',
        sendEncodings: [],
      }
      const VideoTransceiverInit = {
        direction: 'recvonly',
        sendEncodings: [],
      }
      this.pc.addTransceiver('audio', AudioTransceiverInit)
      this.pc.addTransceiver('video', VideoTransceiverInit)
      this.pc
        .createOffer()
        .then((desc) => {
          log(this.TAG, 'offer:', desc.sdp)
          this.pc.setLocalDescription(desc).then(() => {
            axios({
              method: 'post',
              url: this.options.zlmsdpUrl,
              responseType: 'json',
              data: desc.sdp,
              headers: {
                'Content-Type': 'text/plain;charset=utf-8',
              },
            }).then((response) => {
              let ret = response.data //JSON.parse(response.data);

              if (ret.code != 0) {
                // mean failed for offer/anwser exchange
                this.dispatch(Events$1.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED, ret)
                return
              }

              let anwser = {}
              anwser.sdp = ret.sdp
              anwser.type = 'answer'
              log(this.TAG, 'answer:', ret.sdp)
              this.pc
                .setRemoteDescription(anwser)
                .then(() => {
                  log(this.TAG, 'set remote sucess')
                })
                .catch((e) => {
                  error(this.TAG, e)
                })
            })
          })
        })
        .catch((e) => {
          error(this.TAG, e)
        })
    }

    start() {
      let videoConstraints = false
      let audioConstraints = false

      if (this.options.useCamera) {
        if (this.options.videoEnable)
          videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA)
        if (this.options.audioEnable)
          audioConstraints = new AudioTrackConstraints(AudioSourceInfo.MIC)
      } else {
        if (this.options.videoEnable) {
          videoConstraints = new VideoTrackConstraints(VideoSourceInfo.SCREENCAST)
          if (this.options.audioEnable)
            audioConstraints = new AudioTrackConstraints(AudioSourceInfo.SCREENCAST)
        } else {
          if (this.options.audioEnable)
            audioConstraints = new AudioTrackConstraints(AudioSourceInfo.MIC)
          else {
            // error shared display media not only audio
            error(this.TAG, 'error paramter')
          }
        }
      }

      if (
        this.options.resolution.w != 0 &&
        this.options.resolution.h != 0 &&
        typeof videoConstraints == 'object'
      ) {
        videoConstraints.resolution = new Resolution(
          this.options.resolution.w,
          this.options.resolution.h
        )
      }

      MediaStreamFactory.createMediaStream(
        new StreamConstraints(audioConstraints, videoConstraints)
      )
        .then((stream) => {
          this._localStream = stream
          this.dispatch(Events$1.WEBRTC_ON_LOCAL_STREAM, stream)
          const AudioTransceiverInit = {
            direction: 'sendrecv',
            sendEncodings: [],
          }
          const VideoTransceiverInit = {
            direction: 'sendrecv',
            sendEncodings: [],
          }

          if (this.options.simulcast && stream.getVideoTracks().length > 0) {
            VideoTransceiverInit.sendEncodings = [
              {
                rid: 'h',
                active: true,
                maxBitrate: 1000000,
              },
              {
                rid: 'm',
                active: true,
                maxBitrate: 500000,
                scaleResolutionDownBy: 2,
              },
              {
                rid: 'l',
                active: true,
                maxBitrate: 200000,
                scaleResolutionDownBy: 4,
              },
            ]
          }

          if (stream.getAudioTracks().length > 0) {
            this.pc.addTransceiver(stream.getAudioTracks()[0], AudioTransceiverInit)
          } else {
            AudioTransceiverInit.direction = 'recvonly'
            this.pc.addTransceiver('audio', AudioTransceiverInit)
          }

          if (stream.getVideoTracks().length > 0) {
            this.pc.addTransceiver(stream.getVideoTracks()[0], VideoTransceiverInit)
          } else {
            VideoTransceiverInit.direction = 'recvonly'
            this.pc.addTransceiver('video', VideoTransceiverInit)
          }
          /*
	      stream.getTracks().forEach((track,idx)=>{
	          debug.log(this.TAG,track);
	          this.pc.addTrack(track);
	      });
	      */

          this.pc
            .createOffer()
            .then((desc) => {
              log(this.TAG, 'offer:', desc.sdp)
              this.pc.setLocalDescription(desc).then(() => {
                axios({
                  method: 'post',
                  url: this.options.zlmsdpUrl,
                  responseType: 'json',
                  data: desc.sdp,
                  headers: {
                    'Content-Type': 'text/plain;charset=utf-8',
                  },
                }).then((response) => {
                  let ret = response.data //JSON.parse(response.data);

                  if (ret.code != 0) {
                    // mean failed for offer/anwser exchange
                    this.dispatch(Events$1.WEBRTC_OFFER_ANWSER_EXCHANGE_FAILED, ret)
                    return
                  }

                  let anwser = {}
                  anwser.sdp = ret.sdp
                  anwser.type = 'answer'
                  log(this.TAG, 'answer:', ret.sdp)
                  this.pc
                    .setRemoteDescription(anwser)
                    .then(() => {
                      log(this.TAG, 'set remote sucess')
                    })
                    .catch((e) => {
                      error(this.TAG, e)
                    })
                })
              })
            })
            .catch((e) => {
              error(this.TAG, e)
            })
        })
        .catch((e) => {
          this.dispatch(Events$1.CAPTURE_STREAM_FAILED) //debug.error(this.TAG,e);
        }) //const offerOptions = {};

      /*
	    if (typeof this.pc.addTransceiver === 'function') {
	        // |direction| seems not working on Safari.
	        this.pc.addTransceiver('audio', { direction: 'recvonly' });
	        this.pc.addTransceiver('video', { direction: 'recvonly' });
	    } else {
	        offerOptions.offerToReceiveAudio = true;
	        offerOptions.offerToReceiveVideo = true;
	    }
	    */
    }

    _onIceCandidate(event) {
      if (event.candidate) {
        log('Remote ICE candidate: \n ' + event.candidate.candidate) // Send the candidate to the remote peer
      }
    }

    _onTrack(event) {
      if (this.options.element && event.streams && event.streams.length > 0) {
        this.options.element.srcObject = event.streams[0]
        this._remoteStream = event.streams[0]
        this.dispatch(Events$1.WEBRTC_ON_REMOTE_STREAMS, event)
      } else {
        error('element pararm is failed')
      }
    }

    _onIceCandidateError(event) {
      this.dispatch(Events$1.WEBRTC_ICE_CANDIDATE_ERROR, event)
    }

    _onconnectionstatechange(event) {
      this.dispatch(Events$1.WEBRTC_ON_CONNECTION_STATE_CHANGE, this.pc.connectionState)
    }

    close() {
      if (this.pc) {
        this.pc.close()
        this.pc = null
      }

      if (this.options) {
        this.options = null
      }

      if (this._localStream) {
        this._localStream.getTracks().forEach((track, idx) => {
          track.stop()
        })
      }

      if (this._remoteStream) {
        this._remoteStream.getTracks().forEach((track, idx) => {
          track.stop()
        })
      }
    }

    get remoteStream() {
      return this._remoteStream
    }

    get localStream() {
      return this._localStream
    }
  }

  const quickScan = [
    {
      label: '4K(UHD)',
      width: 3840,
      height: 2160,
    },
    {
      label: '1080p(FHD)',
      width: 1920,
      height: 1080,
    },
    {
      label: 'UXGA',
      width: 1600,
      height: 1200,
      ratio: '4:3',
    },
    {
      label: '720p(HD)',
      width: 1280,
      height: 720,
    },
    {
      label: 'SVGA',
      width: 800,
      height: 600,
    },
    {
      label: 'VGA',
      width: 640,
      height: 480,
    },
    {
      label: '360p(nHD)',
      width: 640,
      height: 360,
    },
    {
      label: 'CIF',
      width: 352,
      height: 288,
    },
    {
      label: 'QVGA',
      width: 320,
      height: 240,
    },
    {
      label: 'QCIF',
      width: 176,
      height: 144,
    },
    {
      label: 'QQVGA',
      width: 160,
      height: 120,
    },
  ]
  function GetSupportCameraResolutions$1() {
    return new Promise(function (resolve, reject) {
      let resolutions = []
      let ok = 0
      let err = 0

      for (let i = 0; i < quickScan.length; ++i) {
        let videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA)
        videoConstraints.resolution = new Resolution(quickScan[i].width, quickScan[i].height)
        MediaStreamFactory.createMediaStream(new StreamConstraints(false, videoConstraints))
          .then((stream) => {
            resolutions.push(quickScan[i])
            ok++

            if (ok + err == quickScan.length) {
              resolve(resolutions)
            }
          })
          .catch((e) => {
            err++

            if (ok + err == quickScan.length) {
              resolve(resolutions)
            }
          })
      }
    })
  }
  function GetAllScanResolution$1() {
    return quickScan
  }
  function isSupportResolution$1(w, h) {
    return new Promise(function (resolve, reject) {
      let videoConstraints = new VideoTrackConstraints(VideoSourceInfo.CAMERA)
      videoConstraints.resolution = new Resolution(w, h)
      MediaStreamFactory.createMediaStream(new StreamConstraints(false, videoConstraints))
        .then((stream) => {
          resolve()
        })
        .catch((e) => {
          reject(e)
        })
    })
  }

  console.log('build date:', BUILD_DATE)
  console.log('version:', VERSION)
  const Events = Events$1
  const Media = media
  const Endpoint = RTCEndpoint
  const GetSupportCameraResolutions = GetSupportCameraResolutions$1
  const GetAllScanResolution = GetAllScanResolution$1
  const isSupportResolution = isSupportResolution$1

  exports.Endpoint = Endpoint
  exports.Events = Events
  exports.GetAllScanResolution = GetAllScanResolution
  exports.GetSupportCameraResolutions = GetSupportCameraResolutions
  exports.Media = Media
  exports.isSupportResolution = isSupportResolution

  Object.defineProperty(exports, '__esModule', { value: true })

  return exports
})({})

export default ZLMRTCClient
